hitunglah nilai x pada setiap segitiga di bawah ini!

a) x + 6x + 2x = 180
9x = 180
x = 180/9 = 20°

b) 2x +3x + 90 = 180
5x + 90 = 180
5x = 180-90
5x = 90
x = 90/5
x = 18°

c) 2x + 3x + 4x = 180
9x = 180
x = 180/9
x = 20°

d) 2x + 3x + x = 180
6x = 180
x = 180/6
x = 30°