Tolong dijawab bsk dikumpulin

1.
Keliling = 2 × π × r
= 2 × 22/7 × 21
= 132 cm

Luas = π × r × r
= 22/7 × 21 × 21
= 1386 cm²

2.
Keliling = 2 × π × r
= 2 × 3,14 × 30
= 188,4 cm

Luas = π × r × r
= 3,14 × 30 × 30
= 2826 cm²