Question

In an isosceles triangle , the base angle is twice as large as vertex angle . Find the angles of the triangle .

Answer 1

let vertex angle be x
so, x+2x+2x =180 degrees
5x = 180 degrees
x = 180 / 5
x =36 degrees 
2x+2x+x = 2*36 + 2*36 + 36
= 72 + 72 + 36 
= 180 degrees

Answer 2

Let the equal angles be x, x. Vertex angle =A

x=2A

So x+x+A=180⁰

(Angle sum property)

2x+A=180⁰

4A+A=180⁰

5A=180⁰

A= 180⁰/5=36⁰

x=2A=72

Angles of triangle=

36⁰,72⁰,72⁰.