Year 8 Circumference and Area of Circles Worksheet — Level 2 — Answers
Answer sheet with worked solutions for the Year 8 area & perimeter worksheet.
Year 8 Circumference and Area of Circles Worksheet — Level 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 15 cm. Find its circumference, correct to 1 decimal place.
Answer: 94.2 cm
- C = 2 × π × r = 2 × π × 15
- ≈ 94.2 cm
2.A circle has a diameter of 20 cm. Find its area, correct to 1 decimal place.
Answer: 314.2 cm2
- r = 20 ÷ 2 = 10 cm
- A = π × r2 = π × 102 = π × 100
- ≈ 314.2 cm2
3.A circle has a diameter of 32 cm. Find its circumference, correct to 1 decimal place.
Answer: 100.5 cm
- C = π × d = π × 32
- ≈ 100.5 cm
4.A circle has a radius of 2 cm. Find its area, correct to 1 decimal place.
Answer: 12.6 cm2
- A = π × r2 = π × 22 = π × 4
- ≈ 12.6 cm2
5.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
6.A circle has a diameter of 36 cm. Find its area, correct to 1 decimal place.
Answer: 1017.9 cm2
- r = 36 ÷ 2 = 18 cm
- A = π × r2 = π × 182 = π × 324
- ≈ 1017.9 cm2
7.A circle has a radius of 8 cm. Find its circumference, correct to 1 decimal place.
Answer: 50.3 cm
- C = 2 × π × r = 2 × π × 8
- ≈ 50.3 cm
8.Find the area of a semicircle with a radius of 5 cm, correct to 1 decimal place.
Answer: 39.3 cm2
- A = ½ × π × r2 = ½ × π × 25
- ≈ 39.3 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 17 cm. Find its circumference, correct to 1 decimal place.
Answer: 106.8 cm
- C = 2 × π × r = 2 × π × 17
- ≈ 106.8 cm
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.