apabila luas lingkaran 616cm² maka kelilingnya

Luas = π.r²
616 = 22/7 . r²
r² = 616 : 22/7
r² = 616 x 7/22
r² = 28 x 7
r² = 196
r = √196
r = 14 cm

Keliling = 2.π.r
K = 2 x 22/7 x 14
K = 2 x 22 x 2
K = 88 cm