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

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

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Success TutoringWorksheetsAnswer sheet9th Grade · Mathematics · Area & Perimeter

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

Show your work. 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 radius of 2 cm. Find its circumference, correct to 1 decimal place.

Answer: 12.6 cm

  1. C = 2 × π × r = 2 × π × 2
  2. ≈ 12.6 cm
3.A circle has a radius of 6 cm. What is its diameter?

Answer: 12 cm

The diameter is twice the radius.

4.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
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 diameter of 26 cm. Find its circumference, correct to 1 decimal place.

Answer: 81.7 cm

  1. C = π × d = π × 26
  2. ≈ 81.7 cm
7.A circle has a diameter of 24 cm. Find its circumference, correct to 1 decimal place.

Answer: 75.4 cm

  1. C = π × d = π × 24
  2. ≈ 75.4 cm
8.A circle has a diameter of 32 cm. What is its radius?

Answer: 16 cm

The radius is half the diameter.

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

Answer: 6 cm

The diameter is twice the radius.

10.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
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