bantu jawab ya no. 6

Bab Segitiga
Matematika SMP Kelas VII

<BAC + <ACB = <CBD
(y+10°) + (2y+10°) = 140°
y+10°+2y+10° = 140°
3y+20° = 140°
3y = 140° - 20°
3y = 120°
y = 120°/3
y = 40°

jadi besar sudut CAB = y+10°
= 40°+10°
=50°