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Year 8 Circumference and Area of Circles Worksheet — Level 1 — Practice Set 4 — Answers

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

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Success TutoringWorksheetsAnswer sheetYear 8 · Mathematics · Area & Perimeter

Year 8 Circumference and Area of Circles Worksheet — Level 1 — 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 radius of 18 cm. What is its diameter?

Answer: 36 cm

The diameter is twice the radius.

2.A circle has a diameter of 4 cm. Find its circumference, correct to 1 decimal place.

Answer: 12.6 cm

  1. C = π × d = π × 4
  2. ≈ 12.6 cm
3.A circle has a radius of 17 cm. Find its circumference, correct to 1 decimal place.

Answer: 106.8 cm

  1. C = 2 × π × r = 2 × π × 17
  2. ≈ 106.8 cm
4.A circle has a radius of 15 cm. Find its area, correct to 1 decimal place.

Answer: 706.9 cm2

  1. A = π × r2 = π × 152 = π × 225
  2. ≈ 706.9 cm2
5.A circle has a diameter of 28 cm. Find its circumference, correct to 1 decimal place.

Answer: 88.0 cm

  1. C = π × d = π × 28
  2. ≈ 88.0 cm
6.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
7.A circle has a diameter of 6 cm. Find its circumference, correct to 1 decimal place.

Answer: 18.8 cm

  1. C = π × d = π × 6
  2. ≈ 18.8 cm
8.A circle has a diameter of 10 cm. What is its radius?

Answer: 5 cm

The radius is half the diameter.

9.A circle has a diameter of 8 cm. Find its circumference, correct to 1 decimal place.

Answer: 25.1 cm

  1. C = π × d = π × 8
  2. ≈ 25.1 cm
10.A circle has a radius of 19 cm. Find its area, correct to 1 decimal place.

Answer: 1134.1 cm2

  1. A = π × r2 = π × 192 = π × 361
  2. ≈ 1134.1 cm2
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