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Partition shapes into equal areas

Learning goals

  • Partitions shapes into a stated number of equal-area regions.
  • Checks equality by area rather than shape alone.
  • Expresses each region as a unit fraction of the whole.
  • Explains how the number of equal regions relates to the fraction name.

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Partition shapes into equal areas 1
Use the diagram. What fraction of the whole badge is each part?
Figure for problem 540490

Hints

- Count the equal-area parts in the whole badge. - A unit fraction has \(1\) as its numerator. - Use the number of equal parts as the denominator.

Solution

1. The badge is divided into \(2\) equal-area parts. 2. One of \(2\) equal parts is \(\frac{1}{2}\) of the whole.

Answer

Each part is \(\frac{1}{2}\) of the badge.
Partition shapes into equal areas 2
Which partition divides the rectangle into two equal-area parts, a) or b)?
Figure for problem 550873

Hints

- Compare the widths of the two parts in each panel. - Equal-height rectangles have equal area when their widths are equal.

Solution

1. In a), the vertical segment is halfway across the rectangle, so it makes two rectangles with the same width and height. 2. In b), the segment is not halfway across, so one region is wider than the other. 3. Therefore, only a) makes two equal-area parts.

Answer

Partition a).
Partition shapes into equal areas 3
Use the circle. Are its four regions equal in area? If they are, what fraction of the whole circle is one region?
Figure for problem 550874

Hints

- Compare the sizes of the four sectors in the picture. - A unit-fraction name applies only after you know the parts are equal in area. - Use the number of equal parts in the whole to choose the denominator.

Solution

1. The four sectors in the circle are the same size, so the regions have equal area. 2. The whole is divided into \(4\) equal-area parts. 3. One of \(4\) equal parts is \(\frac{1}{4}\) of the whole.

Answer

Yes. The regions are equal in area, and one region is \(\frac{1}{4}\) of the whole circle.
Partition shapes into equal areas 4
Priya wants to cut this paper rectangle into two pieces of equal area. Each grid square has an area of \(1\) square unit. Where should she make one straight vertical cut?
Figure for problem 558542

Hints

- Count the columns in the whole rectangle. - Find a place that leaves the same number of columns on each side.

Solution

1. The rectangle is \(4\) grid squares wide. 2. A vertical line halfway across gives each part the same width and height. 3. Draw the line \(2\) grid squares from the left side, from top to bottom.

Answer

Draw a vertical line \(2\) grid squares from the left edge, all the way from top to bottom.
Partition shapes into equal areas 5
Each grid square has an area of \(1\) square unit. Do the three strips have equal area? What fraction of the large square is one strip?
Figure for problem 558543

Hints

- Compare the number of grid cells in each strip. - Use the number of equal parts to name one part as a fraction.

Solution

1. Each strip is \(3\) grid squares across and \(1\) square tall, so each contains \(3\) unit squares. 2. All three areas are equal. 3. Each strip is one of \(3\) equal parts, so its fraction is \(\frac{1}{3}\).

Answer

Yes. Each strip is \(\frac{1}{3}\) of the square.
Partition shapes into equal areas 6
Each grid square represents \(1\,\text{square unit}\). Use the grid to find the area of the shaded region and the fraction of the whole that is shaded.
Figure for problem 540476

Hints

- Count the unit squares inside the shaded region. - Count how many equal-size regions make the whole. - Use the number of equal-size regions as the denominator.

Solution

1. The shaded strip contains \(2\) unit squares, so its area is \(2\,\text{square units}\). 2. The rectangle is divided into \(4\) equal vertical strips. 3. One of \(4\) equal-area strips is \(\frac{1}{4}\) of the rectangle.

Answer

The shaded strip has area \(2\,\text{square units}\) and is \(\frac{1}{4}\) of the rectangle.
Partition shapes into equal areas 7
Each grid square represents \(1\,\text{square unit}\). Find the area of each triangle and the fraction of the whole represented by each region.
Figure for problem 540501

Hints

- Compare the two triangles on the grid. - Look for a way one region could fit exactly onto the other. - Use the number of equal-area regions as the fraction denominator.

Solution

1. A diagonal of a square divides it into \(2\) matching triangles, so the triangles have equal area. 2. Share the total area equally: \(16 \div 2 = 8\). 3. Each triangle has area \(8\,\text{square units}\). 4. One of \(2\) equal-area parts is \(\frac{1}{2}\) of the square.

Answer

Each triangle has area \(8\,\text{square units}\) and is \(\frac{1}{2}\) of the square.
Partition shapes into equal areas 8
Use the diagram. a) Are the regions equal in area? Explain how you know. b) What fraction of the whole is each region?
Figure for problem 540514

Hints

- Compare the sizes of the regions in the diagram. - Count how many equal regions make the whole. - Use the number of equal regions as the denominator of a unit fraction.

Solution

1. The three regions are the same size, so they have equal area. 2. The whole is divided into \(3\) equal-area regions. 3. One of \(3\) equal parts is \(\frac{1}{3}\) of the whole.

Answer

a) Yes. The three regions are the same size. b) Each region is \(\frac{1}{3}\) of the whole.
Partition shapes into equal areas 9
Describe one way to divide a rectangle into \(3\) equal-area parts without drawing it. Then write the fraction of the whole represented by one part.

Hints

- Choose a simple way to split a rectangle into three matching shares. - Make sure the three regions have the same amount of area. - Count the equal regions to name one region as a unit fraction.

Solution

1. One valid description is to divide the rectangle into three equal-width strips that run from one side of the rectangle to the opposite side. 2. The strips have equal area because they have the same width and the same height. 3. One of three equal-area parts is \(\frac{1}{3}\) of the whole.

Answer

For example, divide the rectangle into three equal-width strips. Each part represents \(\frac{1}{3}\) of the whole.
Partition shapes into equal areas 10
Which circle, a) or b), is partitioned into thirds? Explain.
Figure for problem 550876

Hints

- Count the regions in each circle. - Then compare their sizes. - “Thirds” means three equal-area parts, not merely three parts.

Solution

1. Circle a) has three equal-area sectors. 2. Circle b) has three sectors, but one is larger than the other two. 3. Thirds require three equal-area parts, so only a) is partitioned into thirds.

Answer

Circle a).
Partition shapes into equal areas 11
Which partition makes \(4\) equal-area parts, a) or b)?
Figure for problem 550877

Hints

- Compare the widths of the left and right regions. - Equal-area rectangles need matching dimensions when their heights are the same. - Check all four regions, not just the top two.

Solution

1. In a), the vertical and horizontal segments both pass through the middle of the rectangle, making four equal rectangles. 2. In b), the vertical segment is off center, so the left regions have less area than the right regions. 3. Therefore, only a) makes four equal-area parts.

Answer

Partition a).
Partition shapes into equal areas 12
A poster has area \(18\,\text{square units}\) and is divided into \(3\) equal-area regions. What is the area of each region, and what fraction of the poster is one region?

Hints

- Share the total area equally among the three regions. - Use the number of equal regions as the fraction denominator.

Solution

1. Divide the total area equally: \(18 \div 3 = 6\,\text{square units}\) per region. 2. One of three equal-area regions is \(\frac{1}{3}\) of the poster.

Answer

Each region has area \(6\,\text{square units}\) and is \(\frac{1}{3}\) of the poster.
Partition shapes into equal areas 13
A circle is divided into \(4\) regions as shown. Are these fourths? Explain.
Figure for problem 550880

Hints

- Having four regions is only one requirement for fourths. - Compare the sizes of the regions. - Use the meaning of equal-area parts.

Solution

1. Fourths require four equal-area parts. 2. The diagram has four regions, but one region is twice the size of each of the three smaller regions. 3. Therefore, the regions are not fourths.

Answer

No. There are \(4\) regions, but they do not have equal area.
Partition shapes into equal areas 14
The triangle is divided into two parts by the segment shown. Use the equal-length marks in the figure. Are the two parts equal in area? What fraction of the whole triangle is each part?
Figure for problem 554037

Hints

- Look at where the dividing segment meets the bottom side. - Compare the two smaller triangles as mirror-image shapes. - If a whole is split into two equal-area parts, think about the unit fraction for one part.

Solution

1. The dividing segment runs through the middle of this left-right symmetric triangle. 2. The two regions are matching mirror images, so they have equal area. 3. The whole triangle is divided into two equal-area parts, so each part is \(\frac{1}{2}\) of the whole.

Answer

Yes. The two parts have equal area, and each part is \(\frac{1}{2}\) of the whole triangle.
Partition shapes into equal areas 15
A paper triangle has been cut into two smaller triangles. Each grid square is \(1\) unit wide. Are the pieces halves of the whole? Explain.
Figure for problem 558544

Hints

- Check where the new line touches the bottom side. - Compare the widths of the two parts along that side. - Halves must have equal area.

Solution

1. The dividing line meets the bottom very close to the left corner. 2. The two triangles reach the same top point, but one has a much longer part of the bottom side than the other. 3. Their areas are not equal, so neither part is half of the whole.

Answer

No. One piece has a bottom side \(1\) grid square long and the other has a bottom side \(5\) squares long. They rise to the same top point, so the wider piece has more area. The pieces are not halves.
Partition shapes into equal areas 16
A garden plan uses a square grid. One line has already cut off a strip on the left. Where should you draw one more vertical line to make three equal-area strips? Give its distance from the right edge in grid squares.
Figure for problem 558545

Hints

- Count the columns in the strip that is already separated. - Would a strip of a different width have the same area if its height stayed the same?

Solution

1. The whole rectangle is \(6\) grid squares wide, and the left strip is \(2\) squares wide. 2. For three equal strips, each must be \(2\) squares wide. 3. Put the second line \(2\) squares from the right edge, straight from top to bottom.

Answer

Draw a vertical line \(2\) grid squares from the right edge, from top to bottom.
Partition shapes into equal areas 17
Each grid square has an area of \(1\) square unit. One diagonal is drawn in the square. Add one straight line to make four equal-area triangles. Name its two endpoints. Use the grid to explain why their areas match, and give the fraction for one triangle.
Figure for problem 558546

Hints

- Picture folding the square to match the two large triangles. - What could you draw to make the smaller pieces match as well?

Solution

1. The drawn line connects \(A\) and \(C\). 2. Connect the other two opposite corners, \(B\) and \(D\). 3. The lines cross in the center. All four triangles have an outside side \(4\) squares long and reach \(2\) squares to the center. 4. Turning the square a quarter turn moves each triangle onto the next one. They have equal area and fill the whole square, so each is \(\frac{1}{4}\) of it.

Answer

Connect \(B\) to \(D\). The lines meet at the square's center. A quarter turn fits each small triangle exactly onto the next, so all four have equal area. Each is \(\frac{1}{4}\) of the square.
Partition shapes into equal areas 18
Nora is making a patchwork quilt. She wants three pieces of equal area from this rectangle, but not all the same shape. Each grid square has an area of \(1\) square unit. One line is already drawn. Where could she add one straight line? Explain why it works.
Figure for problem 558563

Hints

- Count the square units below the drawn line. - Compare the area above the line with the area below it. - What must be true of the two pieces you make from the larger part?

Solution

1. The bottom strip is \(4\) squares across and \(1\) square tall, so its area is \(4\) square units. 2. The top part covers \(8\) square units. Split it into two parts of \(4\) square units each. 3. One way is to draw a vertical line halfway across the upper part, \(2\) squares from the left edge, from the old line to the top. 4. This makes a \(4\)-square bottom rectangle and two \(2\)-by-\(2\) squares. Their areas are equal, but their shapes differ.

Answer

For example, draw a vertical line \(2\) squares from the left edge, starting at the existing line and ending at the top edge. Each piece has an area of \(4\) square units; the bottom part is a long rectangle, and the two top parts are squares.
Partition shapes into equal areas 19
Each grid square represents \(1\,\text{square unit}\). Use the grid to compare the areas of the regions. Are the regions equal in area? Explain. What fraction of the whole is each region?
Figure for problem 540471

Hints

- Count or group the unit squares in each region. - Look for a larger familiar shape that can help you compare two regions. - Equal-area regions do not have to have the same outline.

Solution

1. The left rectangle is \(2\) squares wide and \(2\) squares tall, so its area is \(2 \times 2 = 4\,\text{square units}\). 2. Each triangle on the right is half of a \(4 \times 2\) rectangle. That rectangle has area \(8\,\text{square units}\), so each triangle has area \(8 \div 2 = 4\,\text{square units}\). 3. All three parts have area \(4\,\text{square units}\), so they are equal in area even though they are not the same shape. 4. The whole is divided into \(3\) equal-area parts, so each part is \(\frac{1}{3}\) of the whole.

Answer

Yes. Each part has area \(4\,\text{square units}\), so each part is \(\frac{1}{3}\) of the whole.
Partition shapes into equal areas 20
Each grid square represents \(1\,\text{square unit}\). Use the grid. a) Find the area of A and B. b) Do A and B have equal area? Explain. c) What fraction of the whole is each part?
Figure for problem 540494

Hints

- Count or group the unit squares in A. - Count or group the unit squares in B. - When two regions have equal area and make the whole, each is one half.

Solution

1. Part A is \(3\) squares wide and \(2\) squares tall, so its area is \(3 \times 2 = 6\,\text{square units}\). 2. Part B contains the other \(6\) unit squares, so its area is also \(6\,\text{square units}\). 3. The parts have equal area even though their shapes are different. 4. Each of the \(2\) equal-area parts is \(\frac{1}{2}\) of the whole.

Answer

a) A has area \(6\,\text{square units}\), and B has area \(6\,\text{square units}\). b) Yes. A and B have equal area. c) Each part is \(\frac{1}{2}\) of the whole.
Partition shapes into equal areas 21
A \(6 \times 4\) game board has area \(24\,\text{square units}\). Three students propose area totals for three regions: <table><tr><th>Plan</th><th>Region areas in square units</th></tr><tr><td>A</td><td>\(8, 8, 8\)</td></tr><tr><td>B</td><td>\(6, 9, 9\)</td></tr><tr><td>C</td><td>\(7, 8, 9\)</td></tr></table> Which plan is an equal-area partition? What fraction of the board is each region in that plan?

Hints

- Check whether the three numbers in each row are equal. - Do not confuse having the correct total with having equal parts. - Use the number of equal regions to name one region as a unit fraction.

Solution

1. Each plan totals \(24\,\text{square units}\), but an equal-area partition needs all three region areas to match. 2. Only Plan A has three equal areas: \(8\,\text{square units}\) each. 3. One of \(3\) equal regions is \(\frac{1}{3}\) of the board.

Answer

Plan A. Each region has area \(8\,\text{square units}\) and is \(\frac{1}{3}\) of the board.
Partition shapes into equal areas 22
Each grid square represents \(1\,\text{square unit}\). Use the grid. a) Are all the regions equal in area? Explain. b) What fraction of the whole is each region? c) Do equal-area regions have to have the same shape? Explain.
Figure for problem 540537

Hints

- Use the grid to find the area of each region. - Compare the area values before naming the fraction. - Equal area describes the amount of space, not the outline shape.

Solution

1. The left and right regions are each \(2\) squares wide and \(4\) squares tall, so each has area \(2 \times 4 = 8\,\text{square units}\). 2. The two middle regions together make a \(4 \times 4\) rectangle with area \(16\,\text{square units}\). The diagonal divides that rectangle into two equal-area triangles, so each has area \(16 \div 2 = 8\,\text{square units}\). 3. All four regions have area \(8\,\text{square units}\), so they are equal in area. 4. One of \(4\) equal-area regions is \(\frac{1}{4}\) of the whole. 5. The regions include rectangles and triangles, so equal-area regions do not have to have the same shape.

Answer

a) Yes. Each region has area \(8\,\text{square units}\). b) Each region is \(\frac{1}{4}\) of the whole. c) No. Equal-area regions can have different shapes.
Partition shapes into equal areas 23
Each grid square represents \(1\,\text{square unit}\). Use the final partition. a) How many regions are there? b) Are all the regions equal in area? Explain. c) What fraction of the whole is each smallest region?
Figure for problem 540546

Hints

- Count the final regions shown by the boundary lines. - Compare how many unit squares are in each region. - For part c), compare one smallest region with all the unit squares in the whole rectangle.

Solution

1. The boundary lines divide the rectangle into \(5\) regions. 2. Three regions contain \(2\) unit squares each, while the two smallest regions contain \(1\) unit square each, so the regions are not all equal in area. 3. The whole rectangle contains \(8\) equal unit squares. Each smallest region contains \(1\) of them, so each is \(\frac{1}{8}\) of the whole rectangle.

Answer

a) \(5\) regions b) No. c) Each smallest region is \(\frac{1}{8}\) of the whole rectangle.
Partition shapes into equal areas 24
Each grid square represents \(1\,\text{square unit}\). Use the grid. a) Find the area of the large region and the total area of the three smaller regions. b) Find the area of each smaller region. c) What fraction of the whole is each smaller region?
Figure for problem 540551

Hints

- Use the grid to find the dimensions of the large region. - Find the area of one narrow region from its width and height. - Compare one narrow region with the area of the whole grid.

Solution

1. The large region is \(3\) squares wide and \(4\) squares tall, so its area is \(3 \times 4 = 12\,\text{square units}\). 2. The three smaller regions together also cover a \(3 \times 4\) area, so their total area is \(12\,\text{square units}\). 3. Each smaller region is \(1\) square wide and \(4\) squares tall, so each has area \(1 \times 4 = 4\,\text{square units}\). 4. The whole has area \(6 \times 4 = 24\,\text{square units}\). Since \(24 \div 4 = 6\), each smaller region is \(\frac{1}{6}\) of the whole.

Answer

a) The large region has area \(12\,\text{square units}\), and the three smaller regions have total area \(12\,\text{square units}\). b) Each smaller region has area \(4\,\text{square units}\). c) Each smaller region is \(\frac{1}{6}\) of the whole.
Partition shapes into equal areas 25
A rectangle is partitioned into \(4\) smaller rectangles. Two regions measure \(1\,\text{unit} \times 6\,\text{units}\). The other two measure \(2\,\text{units} \times 3\,\text{units}\). a) Are all four regions equal in area? Show how you know. b) The two rectangle sizes have different perimeters. Does that change your answer to part a)? Explain.

Hints

- Find the area of each rectangle size from its side lengths. - Compare the two area results before deciding whether the partition is equal in area. - For part b), decide which measurement matters in the phrase “equal-area.”

Solution

1. Each \(1\,\text{unit} \times 6\,\text{units}\) region has area \(1 \times 6 = 6\,\text{square units}\). 2. Each \(2\,\text{units} \times 3\,\text{units}\) region has area \(2 \times 3 = 6\,\text{square units}\). 3. All four regions therefore have the same area. 4. Equal-area partitions depend on area, not perimeter, so the different perimeters do not change the conclusion.

Answer

a) Yes. Each region has area \(6\,\text{square units}\). b) No. Different perimeters do not prevent the regions from having equal areas.
Partition shapes into equal areas 26
Each grid square represents \(1\,\text{square unit}\). Use the grid. a) Are all the regions equal in area? Explain. b) What fraction of the whole is each wider region? What fraction of the whole is each narrower region?
Figure for problem 540561

Hints

- Use the grid to find the area of each region. - Compare the wider regions with the narrower regions. - Compare each region's area with the area of the whole when finding its fraction.

Solution

1. Each of the two wider regions is \(2\) squares wide and \(2\) squares tall, so each has area \(2 \times 2 = 4\,\text{square units}\). 2. Each of the four narrower regions is \(1\) square wide and \(2\) squares tall, so each has area \(1 \times 2 = 2\,\text{square units}\). 3. The regions do not all have the same area because \(4 \ne 2\). 4. The whole has area \(8 \times 2 = 16\,\text{square units}\). Each wider region is \(\frac{4}{16} = \frac{1}{4}\) of the whole, while each narrower region is \(\frac{2}{16} = \frac{1}{8}\) of the whole.

Answer

a) No. Two regions have area \(4\,\text{square units}\), while four regions have area \(2\,\text{square units}\). b) Each wider region is \(\frac{1}{4}\) of the whole. Each narrower region is \(\frac{1}{8}\) of the whole.
Partition shapes into equal areas 27
A shape with area \(24\,\text{square units}\) is partitioned into \(6\) equal-area pieces. The pieces are rearranged without gaps or overlaps to make a different whole shape. a) What is the area of each piece? b) What fraction of the new whole is each piece?

Hints

- Find one piece's area before thinking about the rearrangement. - Ask what measurements stay unchanged when pieces are moved. - Count the same pieces in the new whole.

Solution

1. Each original piece has area \(24 \div 6 = 4\,\text{square units}\). 2. Rearranging the pieces does not change their areas or the total area. 3. The new whole still contains the same \(6\) equal-area pieces. 4. Each piece is \(\frac{1}{6}\) of the new whole.

Answer

a) \(4\,\text{square units}\) b) \(\frac{1}{6}\)
Partition shapes into equal areas 28
A shape has area \(48\,\text{square units}\) and is supposed to be partitioned into \(8\) equal-area regions. A draft labels five regions \(6\,\text{square units}\) each and three regions \(5\,\text{square units}\) each. a) Do the labels describe an equal-area partition? b) Do the labeled areas add to the whole area? c) What area should every region have?

Hints

- Compare the region labels before adding them. - Check whether their total matches the whole area. - Divide the whole area by the required number of equal regions.

Solution

1. The labels use two different region areas, \(6\,\text{square units}\) and \(5\,\text{square units}\), so they do not describe equal areas. 2. Their total is \(5 \times 6 + 3 \times 5 = 30 + 15 = 45\,\text{square units}\), not \(48\,\text{square units}\). 3. Eight equal regions in an area of \(48\,\text{square units}\) must each have area \(48 \div 8 = 6\,\text{square units}\). 4. Every region should be labeled \(6\,\text{square units}\).

Answer

a) No. b) No; the labels total \(45\,\text{square units}\). c) \(6\,\text{square units}\) per region.
Partition shapes into equal areas 29
A shape has area \(24\,\text{square units}\). Each equal-area part is \(\frac{1}{6}\) of the whole. a) How many equal parts are there? b) What is the area of each part?

Hints

- Read the denominator as the number of equal parts in the whole. - Then share the total area equally among that many parts.

Solution

1. The denominator \(6\) means the whole is divided into \(6\) equal-area parts. 2. Divide the total area by \(6\): \(24 \div 6 = 4\,\text{square units}\).

Answer

a) \(6\) parts b) \(4\,\text{square units}\) per part
Partition shapes into equal areas 30
The rectangle is already divided into two equal-area halves by the vertical segment. Where should one horizontal segment be drawn so the rectangle is divided into \(4\) equal-area parts?
Figure for problem 550881

Hints

- Keep the existing equal left and right halves. - Think about how to cut both halves into equal top and bottom pieces at the same time. - The new segment should cross the entire rectangle.

Solution

1. The vertical segment already makes two equal-width halves. 2. To split both halves equally again, draw a horizontal segment halfway between the top and bottom edges. 3. The new line creates four rectangles with equal width-and-height pairs, so all four areas are equal.

Answer

Draw a horizontal segment through the middle of the rectangle from the left edge to the right edge.
Partition shapes into equal areas 31
Each grid square represents \(1\,\text{square unit}\). The L-shaped whole is divided into three regions. Are the three regions equal in area? Explain, and state what fraction of the whole each region represents.
Figure for problem 554038

Hints

- Count the unit squares in each region separately. - Equal-area parts can have different orientations or outlines. - After checking the areas, use the number of equal parts to name the unit fraction.

Solution

1. The left region covers \(2\) grid squares, so its area is \(2\,\text{square units}\). 2. The middle region also covers \(2\) grid squares, and the right region covers \(2\) grid squares. 3. The three regions therefore have equal area. 4. Since the whole is divided into \(3\) equal-area parts, each region is \(\frac{1}{3}\) of the whole.

Answer

Yes. Each region has area \(2\,\text{square units}\), so each region is \(\frac{1}{3}\) of the whole.
Partition shapes into equal areas 32
A shape is made of \(21\) unit squares. Can it be partitioned into \(4\) equal-area parts without cutting any unit square? Explain.

Hints

- Equal parts would need the same whole-number count of unit squares. - Test nearby equal group sizes. - Compare their totals with \(21\).

Solution

1. If each part had \(5\) unit squares, the total would be \(4 \times 5 = 20\). 2. If each part had \(6\) unit squares, the total would be \(4 \times 6 = 24\). 3. There is no whole-number square count between \(5\) and \(6\) for each part. 4. Therefore, \(21\) unit squares cannot be split into \(4\) equal-area parts without cutting a square.

Answer

No. Four equal groups of whole unit squares cannot total \(21\).
Partition shapes into equal areas 33
Each grid square represents \(1\,\text{square unit}\). Sam says, “The shaded region is \(\frac{1}{64}\) of the whole because the whole has \(64\) unit squares.” Explain Sam’s error and give the area and fraction of the shaded region.
Figure for problem 540525

Hints

- Count the equal strips separately from the unit squares. - Find the area of the shaded strip from its width and height. - A fraction denominator names the number of equal parts in the partition.

Solution

1. The whole grid has area \(8 \times 8 = 64\,\text{square units}\). 2. The partition has \(8\) equal strips, not \(64\) equal strips. 3. One strip has area \(64 \div 8 = 8\,\text{square units}\). 4. One of \(8\) equal strips is \(\frac{1}{8}\) of the grid. Sam used the number of unit squares instead of the number of equal parts as the denominator.

Answer

One strip has area \(8\,\text{square units}\) and is \(\frac{1}{8}\) of the grid. Sam incorrectly used the total number of unit squares as the fraction denominator.
Partition shapes into equal areas 34
A \(6 \times 3\) rectangle has area \(18\,\text{square units}\). Describe one way to partition it into \(3\) equal-area regions so that at least two regions have different shapes. Explain why the areas are equal.

Hints

- First find the area each of the three regions must have. - Describe one simple region with that area. - Think about how the remaining area could be split into two equal parts with a different outline.

Solution

1. Each of three equal-area regions must have area \(18 \div 3 = 6\,\text{square units}\). 2. One valid description is to make a \(2 \times 3\) rectangle on the left, then divide the remaining \(4 \times 3\) rectangle with a diagonal. 3. The left rectangle has area \(6\,\text{square units}\). The remaining rectangle has area \(12\,\text{square units}\), and its diagonal makes two equal triangles of area \(6\,\text{square units}\) each. 4. The three regions therefore have equal area, and the rectangle region has a different shape from the two triangular regions.

Answer

For example, use a \(2 \times 3\) rectangle plus two triangles made by a diagonal across the remaining \(4 \times 3\) rectangle. Each region has area \(6\,\text{square units}\).

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