Question

Luas lingkaran yg kelilingnya 314 dengan phi 3,14 adalah?

Answer 1

K = πd
314 = 3,14 × d
314/3,14 = d
100 = d
50 cm = r

L = πr²
= 3,14 × 50²
= 7.850 cm²

Answer 2

Keliling = 2πr
<=> 314 = 2 x 3,14 x r
<=> 314 = 6,28r
<=> r = 314/6,28
<=> r = 50

Luas = πr²
         = 3,14 x 50²
         = 3,14 x 2.500
         = 7.850 satuan luas