jika busur BC=24cm, maka panjang busur AB adalah...

80/120 = 24/X
120 x 24 = 80 X
2880/80 = X
36 cm = X

Semoga membantu :D

BC/BOC = AB/AOB
24/80 = AB/120
(24) (120) = (80) (AB)
2880 = 80 AB
AB = 2880/ 80
AB = 36 cm