Let third angle be x
Therefore, two equal angles are 2x and 2x.
Now, we know that sum of angles of three angles of a triangle is 180∘.
⇒x+2x+2x=180∘
⇒5x=180∘
⇒x=36∘
Hence, the three angles of the triangle are,
Third angle =36∘
Second angle =72∘
First angle =72∘