berserta caranya,,tolong secepatnya

Sudut a = 30°
Pab = 22 cm

a) α = 360° / 12 = 30°

b) panjang busur AB = (3α° / 360°) x 2 π r
                                  = [(3 x 30°)/360°] x 2 x 22/7 x 14
                                  = 22 cm