6th Grade Circumference and Area of Circles Worksheet — Level 3 — Practice Set 3 — Answers
Answer sheet with worked solutions for the 6th Grade area & perimeter worksheet.
Success TutoringWorksheetsAnswer sheet6th Grade · Mathematics · Area & Perimeter6th Grade Circumference and Area of Circles Worksheet — Level 3 — 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 circumference of 32π cm. Find its radius and its area (leave the area in terms of π).
Answer: r = 16 cm; A = 256π cm2
- C = 2πr, so 2πr = 32π
- r = 16 cm
- A = πr2 = 256π cm2
2.Find the area of a semicircle with a radius of 3 cm, correct to 1 decimal place.
Answer: 14.1 cm2
- A = ½ × π × r2 = ½ × π × 9
- ≈ 14.1 cm2
3.A circle has a diameter of 18 cm. Find its area, correct to 1 decimal place.
Answer: 254.5 cm2
- r = 18 ÷ 2 = 9 cm
- A = π × r2 = π × 92 = π × 81
- ≈ 254.5 cm2
4.A circle has a circumference of 34π cm. Find its radius and its area (leave the area in terms of π).
Answer: r = 17 cm; A = 289π cm2
- C = 2πr, so 2πr = 34π
- r = 17 cm
- A = πr2 = 289π cm2
5.A circle has a radius of 3 cm. Find its area, correct to 1 decimal place.
Answer: 28.3 cm2
- A = π × r2 = π × 32 = π × 9
- ≈ 28.3 cm2
6.Find the area of a semicircle with a radius of 4 cm, correct to 1 decimal place.
Answer: 25.1 cm2
- A = ½ × π × r2 = ½ × π × 16
- ≈ 25.1 cm2
7.A circle has a circumference of 28π cm. Find its radius and its area (leave the area in terms of π).
Answer: r = 14 cm; A = 196π cm2
- C = 2πr, so 2πr = 28π
- r = 14 cm
- A = πr2 = 196π cm2
8.A circle has a diameter of 12 cm. Find its area, correct to 1 decimal place.
Answer: 113.1 cm2
- r = 12 ÷ 2 = 6 cm
- A = π × r2 = π × 62 = π × 36
- ≈ 113.1 cm2
9.A circle has a circumference of 20π cm. Find its radius and its area (leave the area in terms of π).
Answer: r = 10 cm; A = 100π cm2
- C = 2πr, so 2πr = 20π
- r = 10 cm
- A = πr2 = 100π cm2
10.A circle has a radius of 7 cm. Find its area, correct to 1 decimal place.
Answer: 153.9 cm2
- A = π × r2 = π × 72 = π × 49
- ≈ 153.9 cm2
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