Answer:
Base angle = 72
Vertex angle = 18
Step-by-step explanation:
Measure of the base angle = x. But there are two of them. (Definition of isosceles). Keep that in mind.
The vertex angle is 1/4 of one of the base angles. That means that the vertex is 1/4 x
All three angles = 180 degrees.
So we have x + x + x/4 = 180 degrees.
change 1/4x to 0.25x x since 1/4 = 0.25
Equation
x + x + 0.25 = 180
2.5x = 180
Solution
2.5x = 180 Divide by 2.5 on both sides
2.5x/2.5 = 180/2.5
x = 72
Answer
That means that each base angle = 72 degrees
The Vertex Angle = 72/4 = 18
