Printable math worksheet for calculating the area and circumference of circles.

Let’s solve each circle problem step by step. We’ll use these formulas:

- Radius (r) = half of the diameter → r = d ÷ 2
- Diameter (d) = twice the radius → d = 2 × r
- Circumference (C) = π × diameter → C = πd or C = 2πr
- Area (A) = π × radius² → A = πr²

We’ll leave answers in terms of π unless told otherwise — that means “exact” form.

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Problem 1:
Given: Diameter = 8 ft
→ Radius = 8 ÷ 2 = 4 ft
→ Diameter = 8 ft (given)
→ Circumference = π × 8 = 8π ft
→ Area = π × 4² = π × 16 = 16π ft²

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Problem 2:
Given: Radius = 7 cm
→ Radius = 7 cm (given)
→ Diameter = 2 × 7 = 14 cm
→ Circumference = 2 × π × 7 = 14π cm
→ Area = π × 7² = π × 49 = 49π cm²

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Problem 3:
Given: Diameter = 14 m
→ Radius = 14 ÷ 2 = 7 m
→ Diameter = 14 m (given)
→ Circumference = π × 14 = 14π m
→ Area = π × 7² = π × 49 = 49π m²

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Problem 4:
Given: Radius = 9 in.
→ Radius = 9 in. (given)
→ Diameter = 2 × 9 = 18 in.
→ Circumference = 2 × π × 9 = 18π in.
→ Area = π × 9² = π × 81 = 81π in²

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Problem 5:
Given: Diameter = 14 ft
→ Radius = 14 ÷ 2 = 7 ft
→ Diameter = 14 ft (given)
→ Circumference = π × 14 = 14π ft
→ Area = π × 7² = π × 49 = 49π ft²

*(Same as Problem 3, just different units)*

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Problem 6:
Given: Radius = 5 in.
→ Radius = 5 in. (given)
→ Diameter = 2 × 5 = 10 in.
→ Circumference = 2 × π × 5 = 10π in.
→ Area = π × 5² = π × 25 = 25π in²

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Problem 7:
Given: Diameter = 20 m
→ Radius = 20 ÷ 2 = 10 m
→ Diameter = 20 m (given)
→ Circumference = π × 20 = 20π m
→ Area = π × 10² = π × 100 = 100π m²

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Problem 8:
Given: Radius = 8 cm
→ Radius = 8 cm (given)
→ Diameter = 2 × 8 = 16 cm
→ Circumference = 2 × π × 8 = 16π cm
→ Area = π × 8² = π × 64 = 64π cm²

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Problem 9:
Given: Diameter = 4 yd
→ Radius = 4 ÷ 2 = 2 yd
→ Diameter = 4 yd (given)
→ Circumference = π × 4 = 4π yd
→ Area = π × 2² = π × 4 = 4π yd²

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Final Answer:

1) Radius = 4 ft, Diameter = 8 ft, Circumference = 8π ft, Area = 16π ft²
2) Radius = 7 cm, Diameter = 14 cm, Circumference = 14π cm, Area = 49π cm²
3) Radius = 7 m, Diameter = 14 m, Circumference = 14π m, Area = 49π m²
4) Radius = 9 in., Diameter = 18 in., Circumference = 18π in., Area = 81π in²
5) Radius = 7 ft, Diameter = 14 ft, Circumference = 14π ft, Area = 49π ft²
6) Radius = 5 in., Diameter = 10 in., Circumference = 10π in., Area = 25π in²
7) Radius = 10 m, Diameter = 20 m, Circumference = 20π m, Area = 100π m²
8) Radius = 8 cm, Diameter = 16 cm, Circumference = 16π cm, Area = 64π cm²
9) Radius = 2 yd, Diameter = 4 yd, Circumference = 4π yd, Area = 4π yd²