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7th Grade Circumference and Area of Circles Worksheet — Level 3 — Answers

Answer sheet with worked solutions for the 7th Grade area & perimeter worksheet.

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Success TutoringWorksheetsAnswer sheet7th Grade · Mathematics · Area & Perimeter

7th Grade Circumference and Area of Circles Worksheet — Level 3 — Answers

Show your work. Use the π button on your calculator and round to 1 decimal place unless told otherwise.

1.Find the area of a semicircle with a radius of 10 cm, correct to 1 decimal place.

Answer: 157.1 cm2

  1. A = ½ × π × r2 = ½ × π × 100
  2. ≈ 157.1 cm2
2.A circle has a circumference of 22π cm. Find its radius and its area (leave the area in terms of π).

Answer: r = 11 cm; A = 121π cm2

  1. C = 2πr, so 2πr = 22π
  2. r = 11 cm
  3. A = πr2 = 121π cm2
3.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
4.Find the area of a semicircle with a radius of 13 cm, correct to 1 decimal place.

Answer: 265.5 cm2

  1. A = ½ × π × r2 = ½ × π × 169
  2. ≈ 265.5 cm2
5.A circle has a radius of 11 cm. Find its area, correct to 1 decimal place.

Answer: 380.1 cm2

  1. A = π × r2 = π × 112 = π × 121
  2. ≈ 380.1 cm2
6.A circle has a circumference of 12π cm. Find its radius and its area (leave the area in terms of π).

Answer: r = 6 cm; A = 36π cm2

  1. C = 2πr, so 2πr = 12π
  2. r = 6 cm
  3. A = πr2 = 36π cm2
7.Find the area of a semicircle with a radius of 7 cm, correct to 1 decimal place.

Answer: 77.0 cm2

  1. A = ½ × π × r2 = ½ × π × 49
  2. ≈ 77.0 cm2
8.Find the area of a semicircle with a radius of 6 cm, correct to 1 decimal place.

Answer: 56.5 cm2

  1. A = ½ × π × r2 = ½ × π × 36
  2. ≈ 56.5 cm2
9.A circle has a circumference of 36π cm. Find its radius and its area (leave the area in terms of π).

Answer: r = 18 cm; A = 324π cm2

  1. C = 2πr, so 2πr = 36π
  2. r = 18 cm
  3. A = πr2 = 324π cm2
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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