Tolong ya dengan cara keliling lingkaran

A.
r (jari-jari) = 14 cm
phi = 22/7
k (keliling) = ? cm

k = 2 × phi × r
= 2 × 22/7 × 14
= 2 × 22 × 2 = 88 cm

b.
d (diameter) = 40 cm
phi = 3,14
k = ? cm

k = phi × d
= 3,14 × 40
= 125,6 cm

semoga membantu

A.2×π×jari jari=2×22/7×14=88. b.2×π×jari jari=2×22/7×20=616,2