Question

The measure of the vertex angle of an isosceles triangle is 20 less than twice the measure of each base angle. Find the measure of the vertex angle

Answer 1

80

Explanation:

Remark

Every triangle has a measure of 180 degrees.

Equation

Let the base angle = x

x + x + 2x-20 = 180

Solution

4x - 20 = 180

4x = 180 + 20

4x = 200

x = 50

Conclusion

Base angle 1 = 50

Base angle 2 = 50

Vertex angle = 2*50 - 20

Vertex angle = 100 - 20

Vertex angle = 80