9th Grade Circumference and Area of Circles Worksheet — Level 1 — Answers
Answer sheet with worked solutions for the 9th Grade area & perimeter worksheet.
Success TutoringWorksheetsAnswer sheet9th Grade · Mathematics · Area & Perimeter9th Grade Circumference and Area of Circles Worksheet — Level 1 — 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 4 cm. What is its diameter?
Answer: 8 cm
The diameter is twice the radius.
2.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
3.A circle has a diameter of 32 cm. Find its circumference, correct to 1 decimal place.
Answer: 100.5 cm
- C = π × d = π × 32
- ≈ 100.5 cm
4.A circle has a diameter of 28 cm. Find its area, correct to 1 decimal place.
Answer: 615.8 cm2
- r = 28 ÷ 2 = 14 cm
- A = π × r2 = π × 142 = π × 196
- ≈ 615.8 cm2
5.A circle has a radius of 10 cm. Find its area, correct to 1 decimal place.
Answer: 314.2 cm2
- A = π × r2 = π × 102 = π × 100
- ≈ 314.2 cm2
6.A circle has a radius of 20 cm. Find its circumference, correct to 1 decimal place.
Answer: 125.7 cm
- C = 2 × π × r = 2 × π × 20
- ≈ 125.7 cm
7.A circle has a radius of 8 cm. Find its circumference, correct to 1 decimal place.
Answer: 50.3 cm
- C = 2 × π × r = 2 × π × 8
- ≈ 50.3 cm
8.A circle has a radius of 7 cm. What is its diameter?
Answer: 14 cm
The diameter is twice the radius.
9.A circle has a diameter of 4 cm. Find its circumference, correct to 1 decimal place.
Answer: 12.6 cm
- C = π × d = π × 4
- ≈ 12.6 cm
10.A circle has a diameter of 10 cm. Find its circumference, correct to 1 decimal place.
Answer: 31.4 cm
- C = π × d = π × 10
- ≈ 31.4 cm
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