Aimathic
Login | English | Deutsch

Free Math Worksheets

Build your own math worksheets from 21,000 problems for grades 3 to 12, from fractions to calculus. Every problem includes step-by-step solutions.

Lines of symmetry

Click problems to add them to your worksheet.

5189944
Compare the line symmetry of a non-square rectangle and a square. a) How many lines of symmetry does a non-square rectangle have? Describe them. b) How many lines of symmetry does a square have? c) Why does a square have more lines of symmetry?

Hints

- Imagine folding each shape so its edges match. - Compare folds through side midpoints with folds through opposite vertices. - Consider what changes when all four sides are congruent.

Solution

1. A non-square rectangle has \(2\) lines of symmetry. Each passes through the midpoints of a pair of opposite sides. 2. A square has \(4\) lines of symmetry. 3. A square has the same two midpoint lines as a rectangle, and its two diagonals are also lines of symmetry because all four sides are congruent.

Answer

a) \(2\); they pass through the midpoints of opposite sides. b) \(4\) c) The square’s diagonals are also lines of symmetry.
5354644
The pentagon is shown on a geoboard. Is the figure line-symmetric? If so, how many lines of symmetry does it have, and where are they?
Figure for problem 535464

Hints

- Imagine folding the figure along a line so that its edges match exactly. - Look for pairs of vertices that are the same distance from a possible fold line. - Test vertical, horizontal, and diagonal lines.

Solution

1. Reflecting the figure across the vertical line \(x = 2\) maps the left half onto the right half. 2. This line passes through the top vertex \((2, 4)\) and the midpoint of the bottom side \((2, 0)\). 3. No horizontal or diagonal line maps the figure onto itself, so there is exactly one line of symmetry.

Answer

Yes. The figure has exactly one line of symmetry: the vertical line \(x = 2\).
5372284
Original figure O is shown on one side of the red line. Which image—1, 2, or 3—shows the matching half that would make the red line a line of symmetry for the combined figure? Each grid cell represents 1 unit. Compare the orientation and perpendicular distance from the red line.
Figure for problem 537228

Hints

- Imagine folding along the red line. - Matching points must be the same perpendicular distance from the fold line. - Check that the matching half has the reversed orientation. - A vertical shift prevents the halves from matching.

Solution

1. For the red line to be a line of symmetry, every point in the matching half must be the same perpendicular distance from the red line as its partner in figure O. 2. Image 1 has the correct overall position, but it keeps the original orientation instead of reflecting it across the red line. 3. Image 2 reverses the orientation and places every corresponding point the same distance from the red line on the opposite side. 4. Image 3 is shifted 1 unit upward, so the two halves would not match when folded along the red line.

Answer

Image 2
5329364
Does the front view of this unit-cube building have a vertical line of symmetry? Use the top-view plan to decide.
Figure for problem 532936

Hints

- Find the tallest stack in each plan column. - Compare the left and right heights in the front view.

Solution

1. Find the greatest stack height in each column of the plan. The front-view heights are \(\max(1,2,3)=3\), \(\max(4,0,1)=4\), and \(\max(1,2,3)=3\). 2. The left and right columns have the same height, so the front view matches across a vertical line through the middle column.

Answer

Yes, the front view has a vertical line of symmetry.
5372224
Examine figures a) through d). How many lines of symmetry does each figure have? A line of symmetry is a line along which you can fold a figure so that the two halves match exactly.
Figure for problem 537222

Hints

- Imagine folding each figure so that its edges match exactly. - A line of symmetry divides a figure into mirror-image halves. - Check lines through vertices and lines through side midpoints. - For regular polygons, look for repeated symmetry around the center.

Solution

1. Figure a) is a rectangle. It has \(2\) lines of symmetry: one horizontal and one vertical. 2. Figure b) is an equilateral triangle. It has \(3\) lines of symmetry, each passing through a vertex and the midpoint of the opposite side. 3. Figure c) is an isosceles trapezoid. It has \(1\) vertical line of symmetry. 4. Figure d) is a regular hexagon. It has \(6\) lines of symmetry: \(3\) through pairs of opposite vertices and \(3\) through midpoints of opposite sides.

Answer

a) \(2\) lines of symmetry b) \(3\) lines of symmetry c) \(1\) line of symmetry d) \(6\) lines of symmetry
5329684
Marie adds exactly one cube to building G so that its front view has a vertical line of symmetry. Which plan, A, B, C, or D, shows the completed building?
Figure for problem 532968

Hints

- First find the three heights in the front view. - Decide what must change so the left and right heights match. - Each plan must add exactly one cube. - Check the front view made by each plan.

Solution

1. The front-view heights of building G are \(\max(1,2)=2\), \(\max(2,3)=3\), and \(\max(1,1)=1\), so the front view is \((2, 3, 1)\). 2. To make the view symmetric, the right visible column must increase to height \(2\), giving \((2, 3, 2)\). 3. Plan A raises the front-right stack from \(1\) to \(2\), so its front view is \((2, 3, 2)\). Plan B leaves the front view unchanged, Plan C gives \((3, 3, 1)\), and Plan D gives \((2, 4, 1)\).

Answer

Plan A

All problems may be used, copied and printed free of charge for school and tutoring, including paid tutoring. Commercial adaptations as well as publication or redistribution on the internet are not permitted.