Unit 2, Lesson 4
Dilating Lines and Angles
Integrated Math 2
Preparation
Lesson Narrative
In this lesson, students verify experimentally and assert that dilations take angles to congruent angles. Then, after noticing that the dilations seem to take segments to parallel segments, students write a conjecture relating dilations and parallel lines and construct a convincing argument to prove their conjecture (MP3).
Math Community
Today’s activity is for students to individually reflect on the norms generated so far. During the Cool-down, students provide feedback on the norms, sharing those they agree with and those they feel need revision or removal. These suggestions will inform the next version of the classroom norms.
- Comprehend that dilations take angles to congruent angles.
- Prove that a dilation takes a line not passing through the center of the dilation to a parallel line, and leaves a line passing through the center unchanged (orally and in writing).