tolong jawab no 1,2,3,4 pake caranya ya

1. r = 70 m : 2 = 35 m
L = π.r²
L = 22/7 × 35 × 35
L = 22 × 35 × 5
L = 3.850 m²

2. L = π.r²
L = 3,14 × 10 × 10
L = 3,14 × 100
L = 314 cm²

3. r = 4 dm : 2 = 2 dm = 20 cm
L = π.r²
L = 3,14 × 20 × 20
L = 314 × 4
L = 1.256 cm²

4. L = 1/2 × π.r²
L = 1/2 × 22/7 × 49 × 49
L = 11 × 7 × 49
L = 3.773 cm²