kak gimana caranya yah please dong dijawab

tinggi CD = BC sin B
CD = 20 x sin 30
CD = 20 x 1/2 = 10
alas AB = AD + DB
AB = CD x tan 30 + BC cos 30
AB = 10 x (1/3)akar 3 + 20 x (1/2)akar 3
AB = (10/3)akar 3 + 10 akar 3
AB = (40/3)akar 3
luas = 1/2 x 10 x (40/3)akar 3
= (200/3) akar 3 cm^2