tolong jawab no2 dan beserta caranya

jawab

panjang busur = p = 22 cm
a = 120

panjang busur = 120 /360 x keliling lingkaran
22 = 1/3 x 2 x 22/7 x r
22 = 44/21 r
r = 22 x 21/44
r = 21/2 = 10,5