Circumference and area of circles

Worksheet: Circumference and area of circles

Name:Class:

Answer the questions.

1. Which formula gives the circumference of a circle with diameter d?
   a) 2 × db) π × dc) π × d ÷ 2d) π × d²
2. A circle has diameter 10 cm. Using π = 3.14, what is its circumference?
   a) 15.7 cmb) 31.4 cmc) 314 cmd) 62.8 cm
3. A round pond has diameter 5 m. Using π = 3.14, what is its circumference?
   a) 15.7 mb) 31.4 mc) 7.85 md) 78.5 m
4. Which formula gives the area of a circle with radius r?
   a) 2 × π × rb) π × dc) π × r × 2d) π × r²
5. A circle has radius 3 cm. Using π = 3.14, what is its area?
   a) 18.84 cm²b) 28.26 cm²c) 84.78 cm²d) 9.42 cm²
6. A circle has radius 10 cm. Using π = 3.14, what is its area?
   a) 31.4 cm²b) 314 cm²c) 3140 cm²d) 62.8 cm²
7. A circular plate has diameter 20 cm. What is its radius?
   a) 10 cmb) 20 cmc) 40 cmd) 5 cm
8. A circle has diameter 8 cm. Using π = 3.14, what is its area?
   a) 100.48 cm²b) 200.96 cm²c) 25.12 cm²d) 50.24 cm²
9. A circle has area 314 cm² (π = 3.14). What is its radius?
   a) 10 cmb) 100 cmc) 31.4 cmd) 5 cm
10. A semicircle is half of a circle with radius 10 cm. Using π = 3.14, what is its area?
    a) 157 cm²b) 314 cm²c) 62.8 cm²d) 78.5 cm²
11. The value 3.14 is only an approximation of pi.
    a) Trueb) False
12. If you double the radius of a circle, its area also doubles.
    a) Trueb) False
13. The area of a semicircle is half the area of the full circle with the same radius.
    a) Trueb) False
14. A circle has circumference 31.4 cm. Using π = 3.14, what is its diameter in cm?
15. What is the radius of a circle with diameter 14 cm?
16. A semicircle has radius 2 cm. Using π = 3.14, what is its area in cm²?