Question

What is the measure of a base angle of an isosceles triangle if the measure of the vertex angle is 80 less than the sum of the measures of the base angles?

Answer 1

Answer: 65 °

Explanation:

Let x = measure of a base angle

Base angles of an isosceles triangle are equal

Sum of interior angles of a triangle is always 180:

x + x + (2x - 80) = 180

4x - 80 = 180

4x = 260

x = 65