tolong pakai cara nomor 3 dan 4

3) karena sejajar sehingga 3a + 2a + a = 90
6a = 90
a = 15
AOB = 3a = 3(15)
= 45°
BOC = 2a = 2(15)
= 30°
COD = a = 1(15)
= 15°

4)POQ = 90°
QOR = 30° (karena bertolak belakang)
ROS = 60°
SOT = 90°
TOU = 30°