The lesson begins with students engaging in a whole-class review of the CPCTC Theorem (if two triangles are congruent, then corresponding sides are congruent and corresponding angles are congruent). Following the review, students participate in a min-lesson on how to prove that two triangles are congruent without comparing the measures of ALL the corresponding sides and corresponding angles. The first part of the launch is a hands-on activity in which students must determine which triangles are congruent in given sets. Students are provided with limited angle measures and side lengths for each set of triangles. Through deduction, students should informally recognize that triangles are congruent if they meet at least three particular criteria.
Congruent Triangles & Developing Congruence Criteria - 2 lessons