54216510
A geometry app copies the length of segment \(\overline{AB}\) onto a target line \(m\) through point \(P\). It creates a circle centered at \(P\) with radius \(AB\). The circle intersects \(m\) at points \(U\) and \(V\), on opposite sides of \(P\).
a) Explain why both \(U\) and \(V\) are valid endpoints of a copy of \(\overline{AB}\) starting at \(P\).
b) How many valid endpoints would remain if the target were a ray starting at \(P\) instead of the full line \(m\)?
c) Express \(UV\) in terms of \(AB\).
Hints
- Use the defining property of every point on the circle.
- Compare how many directions extend from \(P\) on a line and on a ray.
- Use the order \(U\)-\(P\)-\(V\) to relate the lengths.
Solution
1. Both \(U\) and \(V\) lie on the circle centered at \(P\) with radius \(AB\), so \(PU=AB\) and \(PV=AB\).
2. A full line extends in both directions from \(P\), so it meets the circle once on each side. A ray extends in only one direction, so it contains only one of those intersections.
3. Since \(P\) lies between \(U\) and \(V\), \(UV=UP+PV=AB+AB=2AB\).
Answer
a) Both are valid because \(PU=PV=AB\).
b) One valid endpoint.
c) \(UV=2AB\).
