Part 3 of Similarity

Here are two similar polygons.Measure the side lengths and angles of each polygon. What do you notice?

Each figure shows a pair of similar triangles, one contained in the other. For each pair, describe a point and a scale factor to use for a dilation moving the larger triangle to the smaller one. Use a measurement tool to find the scale factor.

Triangle DEF is a dilation of triangle ABC with scale factor 2. In triangle ABC, the largest angle measures 82∘. What is the largest angle measure in triangle DEF?

1. 41∘
2. 82∘
3. 123∘
4. 164∘