Question 125886
The total number of degrees in a triangle is 180.  One of the properties of an isosceles triangle is that it has two congruent(equal) base angles.

If one of the base angles is 64 degrees that means the other base angle is 64 degrees.

Let X = The measure of the vertex angle.

1. Base + Base + Vertex = 180

2. 64 + 64 + X = 180

3. 128 + X = 180

4. X = 52

The measure of the vertex angle in this triangle is 52 degrees.