Year 9 Circumference and Area of Circles Worksheet — Level 1 — Practice Set 2 — 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 2 — 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 10 cm. What is its diameter?
Answer: 20 cm
The diameter is twice the radius.
2.A circle has a radius of 18 cm. What is its diameter?
Answer: 36 cm
The diameter is twice the radius.
3.A circle has a radius of 3 cm. Find its area, correct to 1 decimal place.
Answer: 28.3 cm2
- A = π × r2 = π × 32 = π × 9
- ≈ 28.3 cm2
4.A circle has a radius of 16 cm. Find its circumference, correct to 1 decimal place.
Answer: 100.5 cm
- C = 2 × π × r = 2 × π × 16
- ≈ 100.5 cm
5.A circle has a diameter of 30 cm. Find its circumference, correct to 1 decimal place.
Answer: 94.2 cm
- C = π × d = π × 30
- ≈ 94.2 cm
6.A circle has a radius of 16 cm. Find its area, correct to 1 decimal place.
Answer: 804.2 cm2
- A = π × r2 = π × 162 = π × 256
- ≈ 804.2 cm2
7.A circle has a radius of 8 cm. Find its area, correct to 1 decimal place.
Answer: 201.1 cm2
- A = π × r2 = π × 82 = π × 64
- ≈ 201.1 cm2
8.A circle has a diameter of 30 cm. What is its radius?
Answer: 15 cm
The radius is half the diameter.
9.A circle has a radius of 4 cm. What is its diameter?
Answer: 8 cm
The diameter is twice the radius.
10.A circle has a radius of 6 cm. What is its diameter?
Answer: 12 cm
The diameter is twice the radius.
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