http://www.ck12.org Chapter 4. Triangles and Congruence
12.
13.
14.
- Find the measures ofxandy.
Summary
This chapter begins with the Triangle Sum Theorem, showing that the sum of the angles in a triangle is a constant.
The definition of congruency is presented and from that foundation the chapter presents other important theorems
related to congruent triangles, such as the Third Angle Theorem and the SSS, SAS, ASA, AAS and HL Triangle
Congruency Theorems.