Tolong Bantu Aku ya teman

A1 + B4 = 180 drajat
8a + (2a+30) = 180
10a + 30 = 180
10a = 180 - 30
10a = 150
a = 150/10
a = 15

A1 = 8a
= 8 . 15
= 120 drajat

B4 = 2a + 30
= 2(15) +30
= 30 + 30
= 60 drajat
atau
B4 = 180 drjat - 120 drajat
= 60 drajat

Ini ya maaf kalau salah..