Pada Gambar diatas, garis PQ//RS. Nilai a + b =...

Mencari a
105 + 5a = 180 (Saling berpelurus)
5a = 180-105
5a = 75
a = 15

Mencari b
105 + 3b = 180
3b = 180-105
3b = 75
b = 25

a+b
15+25= 40 derajat