hitunglah jari -jari lingkaran jika a. kelilingnya 125,6danphi 3,14 b. kelilingnya 88cm Dan phi 22per8

A.
k = 125,6 cm
π = 3,14

k = 2 × π × r
125,6 = 2 × 3,14 × r
125,6 = 6,28 × r
r = 125,6/6,28 = 20 cm

b.
k = 88 cm
π = 22/7

k = 2 × π × r
88 = 2 × 22/7 × r
88 = 44/7 × r
88 × 7/44 = r
2 × 7 = r
r = 14 cm