luas lingkaran yg keliling 62,8 dm dan phi 3,14 adalah

K = πd
62,8 = 3,14.d
d = 20 dm

r = ½ d
r = ½ 20
r = 10

L = π.r²
L = 3,14 .10²
L = 314 dm²

k = Π × d
62,8 = 3,14 × d
d = 62,8 ÷ 3,14
d = 20 dm
.
r = 20 ÷ 2 = 10 dm
.
.
L = Π × r²
L = 3,14 × 10 × 10
L = 314 dm²