Tolong Jawab Beserta Caranya

Sdt AOB/360 = AB/2 phi R
72/360 = 44/ (2 x 22/7 x R)
1/5 = 22/(22/7 x R)
(22/7) x R = 5 x 22
R = (5 x 22) x 7/22
R = 5 x 7 = 35 cm