tolong ya no 20-23 pakai cara

23. 180°=4x+3x+5x
180°=12x
x =180°:12
x =15°
jawabannya A

20) 5x + 4x = 90*
9x = 90*
x = 10*
<CBD = 5x = 5(10*) = 50* (jawaban C)

21) (4a+4)* + (9a+7)* = 180*
13a* + 11* = 180*
13a* = 180* - 11*
13a* = 169*
a = 169* ÷ 13
a = 13*
<CBD = 9a+7* = 9(13*) + 7* = 124*
(jawaban A)

23) 5x + 3x + 4x = 180*
12x = 180*
x = 180* ÷ 12
x = 15* (jawaban A)