Lesson 12: Practice Problems

Problem 1

Triangle $D E F$ is a dilation of triangle $A B C$ with scale factor 2. In triangle $A B C$ , the largest angle measures $82^{\circ}$ . What is the largest angle measure in triangle $D E F$ ?

$41^{\circ}$
$82^{\circ}$
$123^{\circ}$
$164^{\circ}$

Problem 2

Draw two polygons that are similar but could be mistaken for not being similar. Explain why they are similar.

Problem 3

Draw two polygons that are not similar but could be mistaken for being similar. Explain why they are not similar.

Problem 4

These two triangles are similar. Find side lengths $a$ and $b$ . Note: the two figures are not drawn to scale.

A triangle with side lengths 9, b, 21. A triangle with side lengths 3, 5, a.

Problem 5

Jada claims that $B^{'} C^{'} D^{'}$ is a dilation of $B C D$ using $A$ as the center of dilation.

What are some ways you can convince Jada that her claim is not true?

Dilation point A and line segments BCD and B'C'D'

Problem 6 From Unit 1 Lesson 7

Draw a horizontal line segment $A B$ .
- Rotate segment $A B$ $90^{\circ}$ counterclockwise around point $A$ . Label any new points.
- Rotate segment $A B$ $90^{\circ}$ clockwise around point $B$ . Label any new points.
Describe a transformation on segment $A B$ you could use to finish building a square.