Year 9 Circumference and Area of Circles Worksheet — Level 2 — Practice Set 2 — Answers
Answer sheet with worked solutions for the Year 9 area & perimeter worksheet.
Success TutoringWorksheetsAnswer sheetYear 9 · Mathematics · Area & PerimeterYear 9 Circumference and Area of Circles Worksheet — Level 2 — Practice Set 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 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
2.A circle has a diameter of 34 cm. Find its area, correct to 1 decimal place.
Answer: 907.9 cm2
- r = 34 ÷ 2 = 17 cm
- A = π × r2 = π × 172 = π × 289
- ≈ 907.9 cm2
3.Find the area of a semicircle with a radius of 3 cm, correct to 1 decimal place.
Answer: 14.1 cm2
- A = ½ × π × r2 = ½ × π × 9
- ≈ 14.1 cm2
4.A circle has a diameter of 6 cm. Find its area, correct to 1 decimal place.
Answer: 28.3 cm2
- r = 6 ÷ 2 = 3 cm
- A = π × r2 = π × 32 = π × 9
- ≈ 28.3 cm2
5.Find the area of a semicircle with a radius of 8 cm, correct to 1 decimal place.
Answer: 100.5 cm2
- A = ½ × π × r2 = ½ × π × 64
- ≈ 100.5 cm2
6.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
7.A circle has a radius of 19 cm. Find its area, correct to 1 decimal place.
Answer: 1134.1 cm2
- A = π × r2 = π × 192 = π × 361
- ≈ 1134.1 cm2
8.A circle has a diameter of 36 cm. Find its circumference, correct to 1 decimal place.
Answer: 113.1 cm
- C = π × d = π × 36
- ≈ 113.1 cm
9.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
10.Find the area of a semicircle with a radius of 2 cm, correct to 1 decimal place.
Answer: 6.3 cm2
- A = ½ × π × r2 = ½ × π × 4
- ≈ 6.3 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.