rumus lingkaran. tolong jawab

Maaf kalau salah dan maaf kalau kurang jelas

A. Luas = 22/7 × 7^2 = 154cm^2
Kll = 22/7 × 2 × 7 = 44cm

B. Luas = 22/7 × 14^2 = 616cm^2
Kll = 22/7 × 2 × 14 = 88cm

C. Luas = 22/7 × 21^2 = 1.386cm^2
Kll = 22/7 × 2× 21 = 132cm