Radius Diameter Circumference

Does this picture show the diameter or radius of a circle?

• Diameter

• Radius

Is the red line a radius or diameter of the circle?

• Radius

• Diameter

Alex has trained his puppy, Popper, to jump through a ring. According to Alex's measurements and calculations, the ring has a diameter of 3.5 feet. What is the ring's circumference (use 3.14 for pi)?

• 11.32 ft

• 12.25 ft

• 10.99 ft

• 8.75 ft

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

• 10 in

• 2.5 in

• 15.7 in

• 31.4 in 

What is the circumference of this circle?

• 37.68

• 6.28

• 21.25

• 18.84

Mia's bike has wheels with 14 inch diameters. What is the circumference of each wheel?

• 6.28

• 34.54

• 43.96

• 28.26

A dinner plate has a radius of 6 centimeters. What is the circumference?

• 6.28

• 18.84

• 37.68

• 43.96

What is the circumference of a pizza with a 10-inch diameter?

• 31.40

• 28.26

• 25.12

• 18.86

What is the approximate numerical value of this sign?

• 3.11

• 3.14

• 4.13

• 6.28

In words, describe this formula

• The area of a circle is equal to pi times the radius squared

• The circumference of a circle is equal to the pi times the diameter.

• The circumference of a circle is equal to pi times the radius squared

• The area of a circle is equal to pi times the diameter