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Year 9 Circumference and Area of Circles Worksheet — Level 1 — Practice Set 3 — 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 3 — 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 13 cm. Find its circumference, correct to 1 decimal place.

Answer: 81.7 cm

  1. C = 2 × π × r = 2 × π × 13
  2. ≈ 81.7 cm
2.A circle has a diameter of 26 cm. Find its area, correct to 1 decimal place.

Answer: 530.9 cm2

  1. r = 26 ÷ 2 = 13 cm
  2. A = π × r2 = π × 132 = π × 169
  3. ≈ 530.9 cm2
3.A circle has a radius of 7 cm. What is its diameter?

Answer: 14 cm

The diameter is twice the radius.

4.A circle has a diameter of 22 cm. What is its radius?

Answer: 11 cm

The radius is half the diameter.

5.A circle has a radius of 20 cm. Find its area, correct to 1 decimal place.

Answer: 1256.6 cm2

  1. A = π × r2 = π × 202 = π × 400
  2. ≈ 1256.6 cm2
6.A circle has a radius of 12 cm. Find its area, correct to 1 decimal place.

Answer: 452.4 cm2

  1. A = π × r2 = π × 122 = π × 144
  2. ≈ 452.4 cm2
7.A circle has a radius of 14 cm. Find its circumference, correct to 1 decimal place.

Answer: 88.0 cm

  1. C = 2 × π × r = 2 × π × 14
  2. ≈ 88.0 cm
8.A circle has a diameter of 28 cm. What is its radius?

Answer: 14 cm

The radius is half the diameter.

9.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
10.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
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