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8th Grade Circumference and Area of Circles Worksheet — Level 1 — Practice Set 4 — 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 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 10 cm. What is its radius?

Answer: 5 cm

The radius is half the diameter.

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

Answer: 18 cm

The radius is half the diameter.

3.A circle has a diameter of 14 cm. Find its circumference, correct to 1 decimal place.

Answer: 44.0 cm

  1. C = π × d = π × 14
  2. ≈ 44.0 cm
4.A circle has a radius of 10 cm. Find its area, correct to 1 decimal place.

Answer: 314.2 cm2

  1. A = π × r2 = π × 102 = π × 100
  2. ≈ 314.2 cm2
5.A circle has a radius of 18 cm. Find its area, correct to 1 decimal place.

Answer: 1017.9 cm2

  1. A = π × r2 = π × 182 = π × 324
  2. ≈ 1017.9 cm2
6.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
7.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
8.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
9.A circle has a diameter of 38 cm. Find its circumference, correct to 1 decimal place.

Answer: 119.4 cm

  1. C = π × d = π × 38
  2. ≈ 119.4 cm
10.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
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