Answer:
x = 80
Step-by-step explanation:
We know the sum of the angles of a triangle is 180
x+y+z = 180
Since this is an isosceles triangle y=x
x +x + z = 180
We also know that x = 4z
Writing this in terms of x since we want to find angle x
z = 1/4x
x+x+1/4x = 180
Combine like terms
2x +1/4x = 180
Multiply each side by 4 to get rid of fractions
4(2x +1/4x) = 180*4
8x +x =720
9x = 720
Divide by 9
9x/9 = 720/9
x = 80
