This triangle has 60 degrees already. Remember that the sum of all triangles have to be 180. Since we have two y's we can simplify it as 2y + 60 = 180.
We can now set this up as an algebraic equation.
2y + 60 = 180 Subtract 60 from both sides. 2y = 120 Divide both sides by 2 y = 60.