Informal Proofs of Properties of Dilations

In this lesson, students think about the mathematics behind why those statements are true in terms of an informal proof developed through a discussion. Responses should include the basic properties of dilations; for example, lines map to lines, segments to segments, and rays to rays. Students know an informal proof of why dilations are angle-preserving transformations. Students know an informal proof of why dilations map segments to segments, lines to lines, and rays to rays.