sebuah lingkaran luasnya 154cm2 dan Π=22/7.keliling lingkaran tersebut adalah..cm

154 = 22/7 x r^2
r^2 = 154 x 7/22
r^2 = 49
r = 7

K = 22/7 x 14
= 44 cm

L = phi r2
154 = 22/7 x r x r
154 x 7/22 = r2
49 = r2
7 = r

k = 2 phi r
= 2 x 22/7 x 7
= 308/7
= 44