Year 6 Circumference and Area of Circles Worksheet — Level 3 — Practice Set 4 — Answers
Answer sheet with worked solutions for the Year 6 area & perimeter worksheet.
Year 6 Circumference and Area of Circles Worksheet — Level 3 — 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 circumference of 32π cm. Find its radius and its area (leave the area in terms of π).
Answer: r = 16 cm; A = 256π cm2
- C = 2πr, so 2πr = 32π
- r = 16 cm
- A = πr2 = 256π cm2
2.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
3.A circle has a circumference of 34π cm. Find its radius and its area (leave the area in terms of π).
Answer: r = 17 cm; A = 289π cm2
- C = 2πr, so 2πr = 34π
- r = 17 cm
- A = πr2 = 289π cm2
4.A circle has a diameter of 26 cm. Find its area, correct to 1 decimal place.
Answer: 530.9 cm2
- r = 26 ÷ 2 = 13 cm
- A = π × r2 = π × 132 = π × 169
- ≈ 530.9 cm2
5.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
6.A circle has a radius of 20 cm. Find its area, correct to 1 decimal place.
Answer: 1256.6 cm2
- A = π × r2 = π × 202 = π × 400
- ≈ 1256.6 cm2
7.Find the area of a semicircle with a radius of 14 cm, correct to 1 decimal place.
Answer: 307.9 cm2
- A = ½ × π × r2 = ½ × π × 196
- ≈ 307.9 cm2
8.Find the area of a semicircle with a radius of 12 cm, correct to 1 decimal place.
Answer: 226.2 cm2
- A = ½ × π × r2 = ½ × π × 144
- ≈ 226.2 cm2
9.A circle has a circumference of 16π cm. Find its radius and its area (leave the area in terms of π).
Answer: r = 8 cm; A = 64π cm2
- C = 2πr, so 2πr = 16π
- r = 8 cm
- A = πr2 = 64π cm2
10.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
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.