Honors Geometry Section 4.3 cont. Using CPCTC

In order to use one of the 5 congruence postulates / theorems ( )we need to show that 3 parts of one triangle are congruent to 3 parts of a second triangle. SSS, SAS, ASA, AAS, RHL

But once we have the two triangles congruent, we can then state that any of the other 3 pairs of corresponding angles or sides are congruent by which stands for Note that this statement is just the definition of congruent triangles. CPCTC corresponding parts of congruent triangles are congruent

Let’s prove a couple of things from Unit IV.

The Isosceles Triangle Theorem Given: AB = AC Prove: 1) AB = AC1) Given 2) Draw, the altitude from A 2) Every triangle has 3 altitudes

In an isosceles triangle, the median from the vertex angle bisects the angle. Given: Prove: 1) ) Given )