Radius and Diameter Circumference Formulas

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

The radius of a circle is

• The measurement from the center of a circle to an edge of the circle.

• The measurement around the circle

• The measurement from and edge of the circle to another edge through the center

• A line perpendicular to the diameter of the circle

The diameter of a circle is:

• The measurement around the circle.

• The distance from an edge of a circle to another edge.

• The distance from the center of the circle to an edge of a circle

• The distance from an edge of a circle to another edge through the center. 

What is the diameter?

• 8

• 16

• 10

• 4

A Circle has a diameter of 10 centimeters.  What is the circumference of the circle? (Best Choice)

• 5π or about 15.7 cm

• 10π or about 31.4 cm

• 20π or about 62.8 cm

• 100π or about 314 cm 

Sally has car tire with a circumference of 75.36 ft. What is the radius of the car tire and what is the diameter? (Use 3.14 for pi)

• r=12 ft

• d=26 ft

• r=13 ft

• d=24 ft

Given the circumference of a circle is 62.8 meters, find the diameter of the circle.

• 10 meters

• 20 meters

• 30 meters

• 40 meters

• 5 meters

• 10 meters

• 15 meters

• 20 meters

The circumference of a circle is 62.8 inches.  The circle's radius is __ inches.

Mathematical Equivalence

ON

What is the radius?

• 18

• 72

• 38

• 14