Year 9 Circumference and Area of Circles Worksheet — Level 1 — Practice Set 3 — Answers
Answer sheet with worked solutions for the Year 9 area & perimeter worksheet.
Success TutoringWorksheetsAnswer sheetYear 9 · Mathematics · Area & PerimeterYear 9 Circumference and Area of Circles Worksheet — Level 1 — Practice Set 3 — Answers
Show your working. Use the π button on your calculator and round to 1 decimal place unless told otherwise.
1.A circle has a diameter of 40 cm. Find its circumference, correct to 1 decimal place.
Answer: 125.7 cm
- C = π × d = π × 40
- ≈ 125.7 cm
2.A circle has a diameter of 32 cm. Find its circumference, correct to 1 decimal place.
Answer: 100.5 cm
- C = π × d = π × 32
- ≈ 100.5 cm
3.A circle has a diameter of 12 cm. What is its radius?
Answer: 6 cm
The radius is half the diameter.
4.A circle has a radius of 4 cm. Find its circumference, correct to 1 decimal place.
Answer: 25.1 cm
- C = 2 × π × r = 2 × π × 4
- ≈ 25.1 cm
5.A circle has a radius of 15 cm. What is its diameter?
Answer: 30 cm
The diameter is twice the radius.
6.A circle has a radius of 4 cm. Find its area, correct to 1 decimal place.
Answer: 50.3 cm2
- A = π × r2 = π × 42 = π × 16
- ≈ 50.3 cm2
7.A circle has a radius of 14 cm. Find its area, correct to 1 decimal place.
Answer: 615.8 cm2
- A = π × r2 = π × 142 = π × 196
- ≈ 615.8 cm2
8.A circle has a diameter of 28 cm. Find its circumference, correct to 1 decimal place.
Answer: 88.0 cm
- C = π × d = π × 28
- ≈ 88.0 cm
9.A circle has a diameter of 20 cm. Find its circumference, correct to 1 decimal place.
Answer: 62.8 cm
- C = π × d = π × 20
- ≈ 62.8 cm
10.A circle has a radius of 3 cm. What is its diameter?
Answer: 6 cm
The diameter is twice the radius.
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