mohon wktu di percepat

no 27
mencari nilai x
5x + 35 + 4x + 10 = 90
9x + 45 = 90
9x = 90 - 45
9x = 45
x = 5 derajat

sudut BOC = 4x + 10 = 4 . 5 + 10 = 20 + 10 = 30 derajat