Question 987936
Let the base angle be x
The three angles are x, x and x/4
You know the total of the angles in a triangle is 180

{{{x+ x+ x/4 = 180}}}
{{{4x/4 + 4x/4 + x/4 = 180}}}
{{{9x/4 = 180}}}
{{{9x = 180*4}}}
{{{x = (180*4)/9}}}
{{{x = 80}}}
the angles are 80, 80 and 20