angle c is equivalent to 120 because the triangle is isosceles angle a will equal 35 if you add 35 plus 35 together you will get 70 you then minus 70 from 180 and get 110
because angle b and d are congruent and the triangle is isosceles you take 180-c degrees and substitute the degree measure of c to get 180-120 which is 60 you can divide 60 by two to get the measure of and b and d when they are cut in half for the two triangles but the two angle measures are equivalent to 60 degrees.
