A = 4 phi r2 ...(1)
V = 4/3 phi r3
A = 4/3 phi r3 ...(2)
Disubstitusi (1) ke (2)
A = 4/3 phi r3
4 phi r2 = 4 phi r3 / 3
3(4 phi r2 ) = 4 phi r3
12 phi r2 = 4 phi r3
12 phi/4 phi = r3/r2
3 = r
A = 4 phi r2 ...(1)
V = 4/3 phi r3
A = 4/3 phi r3 ...(2)
Disubstitusi (1) ke (2)
A = 4/3 phi r3
4 phi r2 = 4 phi r3 / 3
3(4 phi r2 ) = 4 phi r3
12 phi r2 = 4 phi r3
12 phi/4 phi = r3/r2
3 = r
Editor: Rian Ade Maulana