Year 8 Circumference and Area of Circles Worksheet — Level 1 — Practice Set 4 — Answers
Answer sheet with worked solutions for the Year 8 area & perimeter worksheet.
Success TutoringWorksheetsAnswer sheetYear 8 · Mathematics · Area & PerimeterYear 8 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 diameter of 28 cm. Find its area, correct to 1 decimal place.
Answer: 615.8 cm2
- r = 28 ÷ 2 = 14 cm
- A = π × r2 = π × 142 = π × 196
- ≈ 615.8 cm2
2.A circle has a diameter of 16 cm. Find its circumference, correct to 1 decimal place.
Answer: 50.3 cm
- C = π × d = π × 16
- ≈ 50.3 cm
3.A circle has a diameter of 38 cm. Find its area, correct to 1 decimal place.
Answer: 1134.1 cm2
- r = 38 ÷ 2 = 19 cm
- A = π × r2 = π × 192 = π × 361
- ≈ 1134.1 cm2
4.A circle has a radius of 14 cm. What is its diameter?
Answer: 28 cm
The diameter is twice the radius.
5.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
6.A circle has a diameter of 12 cm. Find its circumference, correct to 1 decimal place.
Answer: 37.7 cm
- C = π × d = π × 12
- ≈ 37.7 cm
7.A circle has a diameter of 38 cm. Find its circumference, correct to 1 decimal place.
Answer: 119.4 cm
- C = π × d = π × 38
- ≈ 119.4 cm
8.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
9.A circle has a diameter of 30 cm. Find its area, correct to 1 decimal place.
Answer: 706.9 cm2
- r = 30 ÷ 2 = 15 cm
- A = π × r2 = π × 152 = π × 225
- ≈ 706.9 cm2
10.A circle has a diameter of 20 cm. What is its radius?
Answer: 10 cm
The radius is half the diameter.
Marking tips
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