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![Geometry worksheet to help students complete and write congruent triangle proofs which involve parallel lines and alternate interior angle theorems in flow chart format.](https://static.wixstatic.com/media/49609e_91165b8dafb4410f8a96a9c7d447c4b4.jpg/v1/fill/w_427,h_524,al_c,q_80,usm_0.66_1.00_0.01,enc_auto/49609e_91165b8dafb4410f8a96a9c7d447c4b4.jpg)
![Geometry worksheet to help students complete and write congruent triangle proofs which involve parallel lines and alternate interior angle theorems in two column format.](https://static.wixstatic.com/media/49609e_5341e40f9f02450595512c033172a8e4.jpg/v1/fill/w_428,h_524,al_c,q_80,usm_0.66_1.00_0.01,enc_auto/49609e_5341e40f9f02450595512c033172a8e4.jpg)
Activity 3.8
Assignment 5.15
Parallel Lines in Congruent Triangles Proofs
Objective
Complete and create congruent triangle proofs in triangles with a pair of parallel sides with alternate interior angles.
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Assignment 3.9
About Geometry Worksheet Assignment 5.15
Assignment 5.15 is an introduction to writing proofs for congruent triangles in which the triangles have a pair of parallel sides with alternate interior angles.
Prerequisite Skills: Identify conditions for triangle congruence (SSS, SAS, ASA, AAS, HL) (Assignment 5.5). Name pairs of congruent alternate interior angles determined by parallel lines (Assignment 4.6).
Theorem: Alternate Interior Angles: if two parallel lines are intersected by a transversal, the alternate interior angles are congruent.
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