Transformations + Similarity

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SWBAT use the properties of similarity transformations to establish the AA criterion for two triangles to be similar.

Big Idea

Students will use a pair-share activity and activate their prior knowledge to discover how transformations connect to AA criterion.

Do Now

10 minutes

This Do Now will require students to use their knowledge of transformations, more specifically dilations, in order to enlarge a photograph with given coordinates.  This is a pre-requisite skill that requires students to use repeated reasoning by connecting a prior topic with a new applied situation (MP 8).  The do now provides you with an opportunity to review how to dilate a shape on the coordinate plane, and will reinforce that a dilation produces an image that is not congruent to the pre-image. 

Pair-Share Activity

25 minutes

Practice with Similar Triangles

25 minutes

Activity/Homework and Exit Ticket

20 minutes

The Activity-Homework requires students to work through multiple choice and open response questions focusing on similar triangles with an emphasis on AA criterion, SSS and also the use of transformations to show that shapes are similar. 

The Exit Ticket is a straight-forward formative assessment of students' knowledge of writing similarity statements and also identifying AA criterion.  Teachers can ask students to explain their answers with justification, almost like a proof, if time allows in class (MP 3).