Circle Diameter and Radius

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

• Radius

• Diameter

The diameter is...

• twice the radius

• half the radius

• 4 times the radius

• the radius squared

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

Swimming from one side of this pool through the center to the other side is 12 feet. What is the radius of this pool?

• 32 ft

• 6 ft

• 4 ft

• 12 ft

From the center of this CD to the edge of the CD is 4 inches. How far is the distance all the way across the CD?

• 16 in

• 8 in

• 12 in

• 2 in

The radius of this coin is 7 mm. What is the diameter?

• 3.5 mm

• 14 mm

• 21 mm

• 49 mm

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?

• 5 in

• 10 in

• 3.14 in

• 15.84 in

If I want to cut this pizza in half, the line would be 16 in long. How far do I need to cut if I just want a slice from the center?

• 32 in

• 4 in

• 12 in

• 8 in

What is the radius of this circle?

• 6

• 4

• 3

• 0