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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 16 cm. Find its area, correct to 1 decimal place.

Answer: 201.1 cm2

  1. r = 16 ÷ 2 = 8 cm
  2. A = π × r2 = π × 82 = π × 64
  3. ≈ 201.1 cm2
2.A circle has a diameter of 16 cm. What is its radius?

Answer: 8 cm

The radius is half the diameter.

3.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
4.A circle has a diameter of 30 cm. What is its radius?

Answer: 15 cm

The radius is half the diameter.

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

Answer: 50.3 cm

  1. C = 2 × π × r = 2 × π × 8
  2. ≈ 50.3 cm
6.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
7.A circle has a radius of 7 cm. Find its circumference, correct to 1 decimal place.

Answer: 44.0 cm

  1. C = 2 × π × r = 2 × π × 7
  2. ≈ 44.0 cm
8.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
9.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
10.A circle has a diameter of 12 cm. What is its radius?

Answer: 6 cm

The radius is half the diameter.

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