Lesson 10
1. Lesson 10
1.1. Launch
Module 2: Logic and Geometry
Launch
Recall that two triangles are congruent if all corresponding sides are equal and all corresponding angles are equal. To state it simply: corresponding sides must have the same length and corresponding angles the same measure. For example, the following two triangles are congruent (e.g., the same).
PQ = LM
QR = MN
PR = LN
and
∠P = ∠L
∠Q = ∠M
∠R = ∠N
The symbol 
represents the word congruence. The symbol ∴ represents the word therefore.
represents the word congruence. The symbol ∴ represents the word therefore.
Congruent triangles do not need to have the same orientation. A triangle can be transformed by a translation, rotation, or reflection and the result will still be a congruent triangle.
