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Year 9 Circumference and Area of Circles Worksheet — Level 1 — Practice Set 4 — Answers

Answer sheet with worked solutions for the Year 9 area & perimeter worksheet.

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Success TutoringWorksheetsAnswer sheetYear 9 · Mathematics · Area & Perimeter

Year 9 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 diameter of 28 cm. Find its area, correct to 1 decimal place.

Answer: 615.8 cm2

  1. r = 28 ÷ 2 = 14 cm
  2. A = π × r2 = π × 142 = π × 196
  3. ≈ 615.8 cm2
2.A circle has a diameter of 6 cm. Find its area, correct to 1 decimal place.

Answer: 28.3 cm2

  1. r = 6 ÷ 2 = 3 cm
  2. A = π × r2 = π × 32 = π × 9
  3. ≈ 28.3 cm2
3.A circle has a radius of 18 cm. What is its diameter?

Answer: 36 cm

The diameter is twice the radius.

4.A circle has a diameter of 18 cm. Find its circumference, correct to 1 decimal place.

Answer: 56.5 cm

  1. C = π × d = π × 18
  2. ≈ 56.5 cm
5.A circle has a diameter of 14 cm. What is its radius?

Answer: 7 cm

The radius is half the diameter.

6.A circle has a radius of 10 cm. Find its circumference, correct to 1 decimal place.

Answer: 62.8 cm

  1. C = 2 × π × r = 2 × π × 10
  2. ≈ 62.8 cm
7.A circle has a diameter of 22 cm. Find its circumference, correct to 1 decimal place.

Answer: 69.1 cm

  1. C = π × d = π × 22
  2. ≈ 69.1 cm
8.A circle has a diameter of 30 cm. Find its circumference, correct to 1 decimal place.

Answer: 94.2 cm

  1. C = π × d = π × 30
  2. ≈ 94.2 cm
9.A circle has a diameter of 20 cm. Find its circumference, correct to 1 decimal place.

Answer: 62.8 cm

  1. C = π × d = π × 20
  2. ≈ 62.8 cm
10.A circle has a radius of 3 cm. Find its circumference, correct to 1 decimal place.

Answer: 18.8 cm

  1. C = 2 × π × r = 2 × π × 3
  2. ≈ 18.8 cm
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