jawab lah soal di bawah ini

∠ABD+∠CBD = 180°
(3a+20)°+2a° = 180°
3a°+20°+2a° = 180°
3a°+2a° = 180°-20°
5a° = 160°
a = 160°/5
a = 32

∠ABD =  (3a+20)°
= (3(32)+20)°
= (96+20)°
= 116°

Jawabannya (B)

maaf ya kalo salah