yg no 8 yaa tolong bantu

L = 16 phi cm2
L = phi r^2
16 phi = phi r^2
r^2 = 16 phi / phi
r^2 = 16
r = akar16
r = 4 cm.

K = 2 phi r
K = 2 × phi × 4 cm
K = 8 phi cm.

b. 8 phi cm.