Keliling alas kerucut 14cm dan s 25cm. Vol kerucut?

v = 1/3 x phi x r2 x s
v = 1/3 x 22/7 x 14 x 14 x 25
v = 1/3 x 22 x 2 x 14 x 25
v = 1/3 x 15.400
v = 5.134