Two Proof-Oriented Triangle Theorems Lesson 7.2
Theorem 53:If 2 angles of one triangle are congruent to two angles of a second triangle, then the third angles are congruent. (no-choice Theorem) If <A congruent <D <B congruent <E Then <C congruent <F Since the sum = 180 subtract and get <C congruent <F The triangles do not have to be congruent, the angles do! A F C B DE
Theorem 54: If there exists a correspondence between the vertices of two triangles such that two angles and a non-included side of one triangle are congruent to the corresponding parts of the other, then the triangles are congruent. (AAS)
Given:JM GM GK KJ Conclude: <G <J G M H J K 1. JM GM, GK KJ 2. GMJ, JKG rt s 3. GMJ JKG 4. GHM, JHK vert s 5. GHM JHK 6. G J 1.Given 2. lines from rt s 3.Rt s are 4.Assumed from diagram 5.Vert. s are 6.No Choice Theorem
3x-5 60 x+51 Given: Triangle as marked. Find the m 1. By Ext Theorem 3x – 5 = 60 + (x + 5) 3x – 5 = 65 + x 2x = 70 x = 35 1 is supp to (3x – 5) Then 1 + (3x – 5) = 180 1 + 3(35) – 5 = 180 – 5 = 180 = 180 1 = 80