Jawabanmu

2014-05-31T09:21:35+07:00
Misalkan sudut itu = x
x/360 x 2 phi r = 64
x/360 x 2 x 22/7 x 21 = 64
22x/60 = 64
22x = 64 x 60
x (sudut) = 64x60/22
luas = sudut/360 x phi x r^2
luas = 672 cm^2