Year 9 Circumference and Area of Circles Worksheet — Level 1 — Practice Set 4 — 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 4 — 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 radius of 3 cm. Find its circumference, correct to 1 decimal place.
Answer: 18.8 cm
- C = 2 × π × r = 2 × π × 3
- ≈ 18.8 cm
2.A circle has a radius of 15 cm. Find its area, correct to 1 decimal place.
Answer: 706.9 cm2
- A = π × r2 = π × 152 = π × 225
- ≈ 706.9 cm2
3.A circle has a radius of 2 cm. Find its circumference, correct to 1 decimal place.
Answer: 12.6 cm
- C = 2 × π × r = 2 × π × 2
- ≈ 12.6 cm
4.A circle has a radius of 17 cm. What is its diameter?
Answer: 34 cm
The diameter is twice the radius.
5.A circle has a diameter of 20 cm. What is its radius?
Answer: 10 cm
The radius is half the diameter.
6.A circle has a radius of 11 cm. What is its diameter?
Answer: 22 cm
The diameter is twice the radius.
7.A circle has a radius of 14 cm. Find its circumference, correct to 1 decimal place.
Answer: 88.0 cm
- C = 2 × π × r = 2 × π × 14
- ≈ 88.0 cm
8.A circle has a radius of 6 cm. What is its diameter?
Answer: 12 cm
The diameter is twice the radius.
9.A circle has a diameter of 10 cm. Find its area, correct to 1 decimal place.
Answer: 78.5 cm2
- r = 10 ÷ 2 = 5 cm
- A = π × r2 = π × 52 = π × 25
- ≈ 78.5 cm2
10.A circle has a radius of 16 cm. What is its diameter?
Answer: 32 cm
The diameter is twice the radius.
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