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Year 9 Circumference and Area of Circles Worksheet — Level 1 — 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 — 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 10 cm. What is its radius?

Answer: 5 cm

The radius is half the diameter.

2.A circle has a radius of 17 cm. What is its diameter?

Answer: 34 cm

The diameter is twice the radius.

3.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
4.A circle has a radius of 14 cm. Find its area, correct to 1 decimal place.

Answer: 615.8 cm2

  1. A = π × r2 = π × 142 = π × 196
  2. ≈ 615.8 cm2
5.A circle has a diameter of 10 cm. Find its circumference, correct to 1 decimal place.

Answer: 31.4 cm

  1. C = π × d = π × 10
  2. ≈ 31.4 cm
6.A circle has a diameter of 34 cm. Find its area, correct to 1 decimal place.

Answer: 907.9 cm2

  1. r = 34 ÷ 2 = 17 cm
  2. A = π × r2 = π × 172 = π × 289
  3. ≈ 907.9 cm2
7.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
8.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
9.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
10.A circle has a diameter of 22 cm. What is its radius?

Answer: 11 cm

The radius is half the diameter.

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