Perhatikan gambar di bawah ini,besar sudut BAC adalah?

3x – 5 + x – 10 + 95 = 180
4x + 80 = 180
4x = 180 – 80
4x = 100
x = 100/4 = 25

Besar sudut BAC = 3 (25) -5 = 75 – 5 = 70°