Year 6 Circumference and Area of Circles Worksheet — Level 3 — Practice Set 3 — 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 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 circumference of 18π cm. Find its radius and its area (leave the area in terms of π).
Answer: r = 9 cm; A = 81π cm2
- C = 2πr, so 2πr = 18π
- r = 9 cm
- A = πr2 = 81π cm2
2.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
3.A circle has a radius of 17 cm. Find its area, correct to 1 decimal place.
Answer: 907.9 cm2
- A = π × r2 = π × 172 = π × 289
- ≈ 907.9 cm2
4.A circle has a circumference of 6π cm. Find its radius and its area (leave the area in terms of π).
Answer: r = 3 cm; A = 9π cm2
- C = 2πr, so 2πr = 6π
- r = 3 cm
- A = πr2 = 9π cm2
5.A circle has a circumference of 22π cm. Find its radius and its area (leave the area in terms of π).
Answer: r = 11 cm; A = 121π cm2
- C = 2πr, so 2πr = 22π
- r = 11 cm
- A = πr2 = 121π cm2
6.Find the area of a semicircle with a radius of 11 cm, correct to 1 decimal place.
Answer: 190.1 cm2
- A = ½ × π × r2 = ½ × π × 121
- ≈ 190.1 cm2
7.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
8.A circle has a radius of 11 cm. Find its area, correct to 1 decimal place.
Answer: 380.1 cm2
- A = π × r2 = π × 112 = π × 121
- ≈ 380.1 cm2
9.A circle has a diameter of 32 cm. Find its area, correct to 1 decimal place.
Answer: 804.2 cm2
- r = 32 ÷ 2 = 16 cm
- A = π × r2 = π × 162 = π × 256
- ≈ 804.2 cm2
10.A circle has a radius of 7 cm. Find its area, correct to 1 decimal place.
Answer: 153.9 cm2
- A = π × r2 = π × 72 = π × 49
- ≈ 153.9 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.