This activity is designed to give students practice identifying scenarios in which the 5 major triangle congruence theorems (SSS, SAS, ASA, AAS, and HL) can be used to prove triangle pairs congruent.
Students are given 30 triangle pairs. They are to identify which (if any) theorem can be used to prove the triangles congruent, then write the congruence statement for each pair of congruent triangles. Some pairs can be proven congruent using more than one theorem. In these cases students are to identify all congruence theorems that are applicable. Some pairs do not have enough information to prove the triangles congruent. Students are to determine that these triangles may be congruent, but there is not enough information to prove that conclusion. Vertical angles are not marked congruent, neither are sides that are shared between two triangles. It is assumed that students will be able to recognize that vertical angles are congruent and that shared sides are congruent based on the Reflexive Property of Congruence.
This activity could easily be extended by requiring students to explain in writing why specific triangle pairs cannot be proven congruent, or why specific pairs could be proven congruent using more than one method. Also, scaffolding, such as using multiple colored highlighters to mark the congruent parts, can be easily embedded for struggling students.