May 13, 2015

Students understand that similarity is reflexive, symmetric, and transitive.

Students recognize that if two triangles are similar, there is a correspondence such that corresponding pairs of angles have the same measure and corresponding sides are proportional. Conversely, they know that if there is a correspondence satisfying these conditions, then there is a similarity transformation taking one triangle to the other respecting the correspondence.

Teacher and Student versions of full lesson from engageNY

- Mathematics > General
- Mathematics > Geometry

- Grade 9
- Grade 10

Reason abstractly and quantitatively.

Construct viable arguments and critique the reasoning of others.

Use appropriate tools strategically.

Attend to precision.

Look for and make use of structure.

Given two figures, use the definition of similarity in terms of similarity transformations to decide if they are similar; explain using similarity transformations the meaning of similarity for triangles as the equality of all corresponding pairs of angles and the proportionality of all corresponding pairs of sides.