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Year 8 Circumference and Area of Circles Worksheet — Level 3 — Practice Set 2 — Answers

Answer sheet with worked solutions for the Year 8 area & perimeter worksheet.

Success TutoringWorksheetsAnswer sheetYear 8 · Mathematics · Area & Perimeter

Year 8 Circumference and Area of Circles Worksheet — Level 3 — 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 radius of 6 cm. Find its area, correct to 1 decimal place.

Answer: 113.1 cm2

  1. A = π × r2 = π × 62 = π × 36
  2. ≈ 113.1 cm2
2.A circle has a radius of 16 cm. Find its area, correct to 1 decimal place.

Answer: 804.2 cm2

  1. A = π × r2 = π × 162 = π × 256
  2. ≈ 804.2 cm2
3.Find the area of a semicircle with a radius of 12 cm, correct to 1 decimal place.

Answer: 226.2 cm2

  1. A = ½ × π × r2 = ½ × π × 144
  2. ≈ 226.2 cm2
4.Find the area of a semicircle with a radius of 19 cm, correct to 1 decimal place.

Answer: 567.1 cm2

  1. A = ½ × π × r2 = ½ × π × 361
  2. ≈ 567.1 cm2
5.A circle has a circumference of 38π cm. Find its radius and its area (leave the area in terms of π).

Answer: r = 19 cm; A = 361π cm2

  1. C = 2πr, so 2πr = 38π
  2. r = 19 cm
  3. A = πr2 = 361π cm2
6.Find the area of a semicircle with a radius of 13 cm, correct to 1 decimal place.

Answer: 265.5 cm2

  1. A = ½ × π × r2 = ½ × π × 169
  2. ≈ 265.5 cm2
7.Find the area of a semicircle with a radius of 18 cm, correct to 1 decimal place.

Answer: 508.9 cm2

  1. A = ½ × π × r2 = ½ × π × 324
  2. ≈ 508.9 cm2
8.A circle has a radius of 10 cm. Find its area, correct to 1 decimal place.

Answer: 314.2 cm2

  1. A = π × r2 = π × 102 = π × 100
  2. ≈ 314.2 cm2
9.A circle has a circumference of 28π cm. Find its radius and its area (leave the area in terms of π).

Answer: r = 14 cm; A = 196π cm2

  1. C = 2πr, so 2πr = 28π
  2. r = 14 cm
  3. A = πr2 = 196π cm2
10.Find the area of a semicircle with a radius of 10 cm, correct to 1 decimal place.

Answer: 157.1 cm2

  1. A = ½ × π × r2 = ½ × π × 100
  2. ≈ 157.1 cm2
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