7th Grade Circumference and Area of Circles Worksheet — Level 2 — Practice Set 4 — Answers
Answer sheet with worked solutions for the 7th Grade area & perimeter worksheet.
7th Grade Circumference and Area of Circles Worksheet — Level 2 — 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 30 cm. Find its area, correct to 1 decimal place.
Answer: 706.9 cm2
- r = 30 ÷ 2 = 15 cm
- A = π × r2 = π × 152 = π × 225
- ≈ 706.9 cm2
2.A circle has a diameter of 22 cm. Find its circumference, correct to 1 decimal place.
Answer: 69.1 cm
- C = π × d = π × 22
- ≈ 69.1 cm
3.A circle has a radius of 15 cm. Find its circumference, correct to 1 decimal place.
Answer: 94.2 cm
- C = 2 × π × r = 2 × π × 15
- ≈ 94.2 cm
4.Find the area of a semicircle with a radius of 18 cm, correct to 1 decimal place.
Answer: 508.9 cm2
- A = ½ × π × r2 = ½ × π × 324
- ≈ 508.9 cm2
5.Find the area of a semicircle with a radius of 16 cm, correct to 1 decimal place.
Answer: 402.1 cm2
- A = ½ × π × r2 = ½ × π × 256
- ≈ 402.1 cm2
6.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
7.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
8.A circle has a diameter of 24 cm. Find its area, correct to 1 decimal place.
Answer: 452.4 cm2
- r = 24 ÷ 2 = 12 cm
- A = π × r2 = π × 122 = π × 144
- ≈ 452.4 cm2
9.A circle has a diameter of 20 cm. Find its circumference, correct to 1 decimal place.
Answer: 62.8 cm
- C = π × d = π × 20
- ≈ 62.8 cm
10.Find the area of a semicircle with a radius of 17 cm, correct to 1 decimal place.
Answer: 454.0 cm2
- A = ½ × π × r2 = ½ × π × 289
- ≈ 454.0 cm2
Marking tips
- Give credit for correct method even when the final answer slips — the working shows where the thinking went right.
- For open-ended tasks, use the success criteria as a checklist rather than looking for one "right" answer.
- Celebrate what went well first, then pick one thing to work on next.