Bantu No.8,9,dan10... Please...

nomor sembilan dan sepuluh

No. 8
Diketahui :
K = 62,8 cm
π = 3,14

Ditanya :
r = ?

Jawab :
r = K/2.π
= 62,8/2 × 3,14
= 10 cm (C)

No. 9
Diketahui :
d = 7 cm
π = 22/7

Ditanya :
L = ?

Jawab :
L = 1/4.π.d²
= 1/4.22/7.7²
= 1/4.22/7.49
= 38,5 cm (A)

No. 10
Diketahui :
L = 616 cm²
π = 22/7

Ditanya :
r = ?

Jawab :
r² = L/π
= 616/ 22/7
= 616 × 7/22
= 196
r² = √196
= 14 cm (B)