Year 7 Circumference and Area of Circles Worksheet — Level 3 — Answers
Answer sheet with worked solutions for the Year 7 area & perimeter worksheet.
Year 7 Circumference and Area of Circles Worksheet — Level 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 radius of 6 cm. Find its area, correct to 1 decimal place.
Answer: 113.1 cm2
- A = π × r2 = π × 62 = π × 36
- ≈ 113.1 cm2
2.A circle has a diameter of 14 cm. Find its area, correct to 1 decimal place.
Answer: 153.9 cm2
- r = 14 ÷ 2 = 7 cm
- A = π × r2 = π × 72 = π × 49
- ≈ 153.9 cm2
3.A circle has a circumference of 24π cm. Find its radius and its area (leave the area in terms of π).
Answer: r = 12 cm; A = 144π cm2
- C = 2πr, so 2πr = 24π
- r = 12 cm
- A = πr2 = 144π cm2
4.A circle has a circumference of 20π cm. Find its radius and its area (leave the area in terms of π).
Answer: r = 10 cm; A = 100π cm2
- C = 2πr, so 2πr = 20π
- r = 10 cm
- A = πr2 = 100π cm2
5.Find the area of a semicircle with a radius of 7 cm, correct to 1 decimal place.
Answer: 77.0 cm2
- A = ½ × π × r2 = ½ × π × 49
- ≈ 77.0 cm2
6.Find the area of a semicircle with a radius of 19 cm, correct to 1 decimal place.
Answer: 567.1 cm2
- A = ½ × π × r2 = ½ × π × 361
- ≈ 567.1 cm2
7.A circle has a radius of 10 cm. Find its area, correct to 1 decimal place.
Answer: 314.2 cm2
- A = π × r2 = π × 102 = π × 100
- ≈ 314.2 cm2
8.Find the area of a semicircle with a radius of 17 cm, correct to 1 decimal place.
Answer: 454.0 cm2
- A = ½ × π × r2 = ½ × π × 289
- ≈ 454.0 cm2
9.A circle has a diameter of 4 cm. Find its area, correct to 1 decimal place.
Answer: 12.6 cm2
- r = 4 ÷ 2 = 2 cm
- A = π × r2 = π × 22 = π × 4
- ≈ 12.6 cm2
10.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
Marking tips
- Give credit for correct method even when the final answer slips — the working shows where the thinking went right.
- For open-ended tasks, use the success criteria as a checklist rather than looking for one "right" answer.
- Celebrate what went well first, then pick one thing to work on next.