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9th Grade Circumference and Area of Circles Worksheet — Level 1 — Practice Set 2 — 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 2 — 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 radius of 13 cm. What is its diameter?

Answer: 26 cm

The diameter is twice the radius.

2.A circle has a radius of 15 cm. What is its diameter?

Answer: 30 cm

The diameter is twice the radius.

3.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
4.A circle has a diameter of 22 cm. Find its area, correct to 1 decimal place.

Answer: 380.1 cm2

  1. r = 22 ÷ 2 = 11 cm
  2. A = π × r2 = π × 112 = π × 121
  3. ≈ 380.1 cm2
5.A circle has a radius of 9 cm. What is its diameter?

Answer: 18 cm

The diameter is twice the radius.

6.A circle has a diameter of 36 cm. Find its area, correct to 1 decimal place.

Answer: 1017.9 cm2

  1. r = 36 ÷ 2 = 18 cm
  2. A = π × r2 = π × 182 = π × 324
  3. ≈ 1017.9 cm2
7.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
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 diameter of 22 cm. What is its radius?

Answer: 11 cm

The radius is half the diameter.

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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