Answer:

6. circumference-43.96cm²

solution : 2×3.14×7

7.circumference-28.26in²

solution:2×3.14×4.5

8.circumference-75.36mm²

2×3.14×12

9.circumference-47.1cm²

2×3.14×7.5

10.circumference-21.98m²

2×3.14×3.5