What is the measure of the vertex angle of an isosceles triangle if one of its base angles measures 42° and its congruent sides each measure 9 cm? Please express your answer as a number only.

Answer 1

If one base angle is 42, so is the other. And, the three angles total 180.

The length of the sides does not matter.

Answer 2

Triangle XYZ is isosceles. The measure of the vertex angle, Y, is twice the measure of a base angle.

What is true about triangle XYZ? Check all that apply.