Circles: circumference and area

Answer Key - Grade 6 Math Worksheet - Building Confidence

Circle the best answer, or write your answer on the line.

1. 1.

   Kira measures a round clock face. Its diameter is 30 cm. The radius is half of the diameter. What is the radius, in cm?

   15
2. 2.

   Luz measures a round play tent floor. Its diameter is 12 ft. The radius is half of the diameter. What is the radius, in ft?

   6
3. 3.

   Ren measures a round umbrella canopy. Its radius is 6 ft. The diameter is twice the radius. What is the diameter, in ft?

   12
4. 4.

   Zee measures a round cake top with a diameter of 18 cm. The circumference (the distance around a circle) is 3.14 diameters. What is its circumference, in cm? Use π = 3.14.

   56.52
5. 5.

   Bo measures a round jar lid with a diameter of 16 cm. The circumference (the distance around a circle) is 3.14 diameters. What is its circumference, in cm? Use π = 3.14.

   50.24
6. 6.

   Esme measures a round frog pond with a radius of 3 ft. Its area is 3.14 squares, each 3 ft by 3 ft. What is its area, in square ft? Use π = 3.14.

   28.26
7. 7.

   Jun measures a round cookie with a radius of 5 cm. Its area is 3.14 squares, each 5 cm by 5 cm. What is its area, in square cm? Use π = 3.14.

   78.5
8. 8.

   Kira measures a round plate with a radius of 9 cm. Its area is 3.14 squares, each 9 cm by 9 cm. What is its area, in square cm? Use π = 3.14.

   254.34
9. 9.

   Milo measures a round jar lid with a diameter of 14 cm, so its radius is 7 cm. What is its area, in square cm? Use π = 3.14.

   153.86
10. 10.

    Noah measures a round plate with a diameter of 18 cm, so its radius is 9 cm. What is its area, in square cm? Use π = 3.14.

    254.34