I'll solve each circle problem step by step, calculating both circumference and area.
Circle 1: r = 9.5 mm
Circumference = 2πr
= 2 × π × 9.5
= 19π
≈ 19 × 3.14159
≈ 59.69 mm
Area = πr²
= π × (9.5)²
= π × 90.25
≈ 3.14159 × 90.25
≈ 283.53 mm²
Circle 2: r = 2.7 cm
Circumference = 2πr
= 2 × π × 2.7
= 5.4π
≈ 5.4 × 3.14159
≈ 16.96 cm
Area = πr²
= π × (2.7)²
= π × 7.29
≈ 3.14159 × 7.29
≈ 22.90 cm²
Circle 3: r = 7.3 in
Circumference = 2πr
= 2 × π × 7.3
= 14.6π
≈ 14.6 × 3.14159
≈ 45.87 in
Area = πr²
= π × (7.3)²
= π × 53.29
≈ 3.14159 × 53.29
≈ 167.41 in²
Circle 4: r = 3.1 cm
Circumference = 2πr
= 2 × π × 3.1
= 6.2π
≈ 6.2 × 3.14159
≈ 19.48 cm
Area = πr²
= π × (3.1)²
= π × 9.61
≈ 3.14159 × 9.61
≈ 30.19 cm²
Final Answer:
Circle 1 (r = 9.5 mm):
- Circumference = 59.69 mm
- Area = 283.53 mm²
Circle 2 (r = 2.7 cm):
- Circumference = 16.96 cm
- Area = 22.90 cm²
Circle 3 (r = 7.3 in):
- Circumference = 45.87 in
- Area = 167.41 in²
Circle 4 (r = 3.1 cm):
- Circumference = 19.48 cm
- Area = 30.19 cm²
Parent Tip: Review the logic above to help your child master the concept of find the area and circumference of a circle worksheet.
