berapakah luas lingkaran dengan keliling 66cm ???? berikan jalannya

rumus keliling = phi x d
66 = 22/7 x d
d = 66/22 x 7
d = 3 x 7 = 21
r = 21/2

luas = phi x r x r
= 22/7 x 21/2 x 21/2
= 9702/28
= 346,5 cm

K = Πd
66 = 22/7 × d
22/7 × d = 66
d = 7/22 × 66
d = 7 × 3
d = 21 cm
r = ½ × d = ½ × 21 = 10,5 cm

L = ¼ Πd²
L = ¼ × 22/7 × 21 × 21
L = ¼ × 1386
L = 346,5 cm²

semoga membantu dan bermanfaat