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8th Grade Circumference and Area of Circles Worksheet — Level 1 — Practice Set 2 — Answers

Answer sheet with worked solutions for the 8th Grade area & perimeter worksheet.

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Success TutoringWorksheetsAnswer sheet8th Grade · Mathematics · Area & Perimeter

8th 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 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
2.A circle has a diameter of 4 cm. Find its area, correct to 1 decimal place.

Answer: 12.6 cm2

  1. r = 4 ÷ 2 = 2 cm
  2. A = π × r2 = π × 22 = π × 4
  3. ≈ 12.6 cm2
3.A circle has a radius of 2 cm. What is its diameter?

Answer: 4 cm

The diameter is twice the radius.

4.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
5.A circle has a diameter of 40 cm. What is its radius?

Answer: 20 cm

The radius is half the diameter.

6.A circle has a diameter of 18 cm. Find its area, correct to 1 decimal place.

Answer: 254.5 cm2

  1. r = 18 ÷ 2 = 9 cm
  2. A = π × r2 = π × 92 = π × 81
  3. ≈ 254.5 cm2
7.A circle has a radius of 11 cm. Find its circumference, correct to 1 decimal place.

Answer: 69.1 cm

  1. C = 2 × π × r = 2 × π × 11
  2. ≈ 69.1 cm
8.A circle has a radius of 19 cm. Find its area, correct to 1 decimal place.

Answer: 1134.1 cm2

  1. A = π × r2 = π × 192 = π × 361
  2. ≈ 1134.1 cm2
9.A circle has a diameter of 16 cm. What is its radius?

Answer: 8 cm

The radius is half the diameter.

10.A circle has a radius of 14 cm. What is its diameter?

Answer: 28 cm

The diameter is twice the radius.

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