Year 9 Circumference and Area of Circles Worksheet — Level 2 — Practice Set 4 — 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 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 diameter of 22 cm. Find its area, correct to 1 decimal place.
Answer: 380.1 cm2
- r = 22 ÷ 2 = 11 cm
- A = π × r2 = π × 112 = π × 121
- ≈ 380.1 cm2
2.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
3.Find the area of a semicircle with a radius of 16 cm, correct to 1 decimal place.
Answer: 402.1 cm2
- A = ½ × π × r2 = ½ × π × 256
- ≈ 402.1 cm2
4.A circle has a diameter of 16 cm. Find its circumference, correct to 1 decimal place.
Answer: 50.3 cm
- C = π × d = π × 16
- ≈ 50.3 cm
5.A circle has a diameter of 18 cm. Find its circumference, correct to 1 decimal place.
Answer: 56.5 cm
- C = π × d = π × 18
- ≈ 56.5 cm
6.A circle has a radius of 13 cm. Find its circumference, correct to 1 decimal place.
Answer: 81.7 cm
- C = 2 × π × r = 2 × π × 13
- ≈ 81.7 cm
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 14 cm, correct to 1 decimal place.
Answer: 307.9 cm2
- A = ½ × π × r2 = ½ × π × 196
- ≈ 307.9 cm2
9.Find the area of a semicircle with a radius of 20 cm, correct to 1 decimal place.
Answer: 628.3 cm2
- A = ½ × π × r2 = ½ × π × 400
- ≈ 628.3 cm2
10.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
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