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8th Grade Circumference and Area of Circles Worksheet — Level 1 — Practice Set 3 — 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 3 — 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 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
2.A circle has a radius of 12 cm. Find its area, correct to 1 decimal place.

Answer: 452.4 cm2

  1. A = π × r2 = π × 122 = π × 144
  2. ≈ 452.4 cm2
3.A circle has a diameter of 6 cm. What is its radius?

Answer: 3 cm

The radius is half the diameter.

4.A circle has a diameter of 36 cm. What is its radius?

Answer: 18 cm

The radius is half the diameter.

5.A circle has a diameter of 18 cm. What is its radius?

Answer: 9 cm

The radius is half the diameter.

6.A circle has a diameter of 10 cm. Find its area, correct to 1 decimal place.

Answer: 78.5 cm2

  1. r = 10 ÷ 2 = 5 cm
  2. A = π × r2 = π × 52 = π × 25
  3. ≈ 78.5 cm2
7.A circle has a radius of 9 cm. Find its circumference, correct to 1 decimal place.

Answer: 56.5 cm

  1. C = 2 × π × r = 2 × π × 9
  2. ≈ 56.5 cm
8.A circle has a diameter of 12 cm. Find its circumference, correct to 1 decimal place.

Answer: 37.7 cm

  1. C = π × d = π × 12
  2. ≈ 37.7 cm
9.A circle has a diameter of 4 cm. What is its radius?

Answer: 2 cm

The radius is half the diameter.

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

Answer: 78.5 cm2

  1. A = π × r2 = π × 52 = π × 25
  2. ≈ 78.5 cm2
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