Circumference of a Circle DS2

What does "circumference" mean?

• The area of a circle.
• The diameter of a circle.
• The radius of a circle.
• The distance around a circle.

What is the formula for circumference of a circle given the diameter?

• C = 2 * π * r
• C = π * d
• C = π * r^2
• C = d^2 * π

If the radius of a circle is equal to 8 cm, what is the measurement of its diameter?

(a)  

Cynthia wants to buy a round photo frame for her brother. The radius of the photo frame is 9 cm. What is the photo frame’s diameter?

• 12 cm
• 18 cm
• 15 cm
• 20 cm

Steven purchases a bowl. The diameter of the bowl is 14 cm. What is the radius of the bowl?

• 10 cm
• 7 cm
• 8 cm
• 6 cm

Daniel wants to buy cookies for his friend. The radius of a cookie is 5 inches. What is the cookie’s circumference?

• 40.84 inches
• 25.12 inches
• 15.70 inches
• 31.42 inches

A circular swimming pool is 21 feet in diameter. What is the circumference of the pool?

(a)  

If the diameter of a circle is 24 inches, what is the measurement of its radius?

(a)  

Alex has trained his puppy, Popper, to jump through a ring. According to Alex's measurements and calculations, the ring has a diameter of 5 feet. What is the ring's circumference (use 3.14 for pi)?

(a)  

The minute hand (radius) of a clock is 20 cm. What is its circumference?

(a)