Radius and Diameter Circumference Formulas

• center
• diameter
• radius

A straight line from the center of a circle to the circumference is called the ____.

• Diameter

• Circumference

• Radius

• Area

A straight line segment that passes through the center of a circle and whose endpoints lie on the circumference of the circle is called the ____.

• Diameter

• Radius

• Circumference

• Area

What is the radius of a circle when the diameter is 70 m?

• 38 m

• 35 m

• 90 m

• 140 m

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

• Radius

• Diameter

What is the circle's radius?

• 3 m

• 6 m

• 12 m

What is the diameter?

• 8

• 16

• 10

• 4

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

• Diameter

• Radius

What does C represent in the formula:

C = π·d

• Pi

• Circumference

• Diameter

• Area

What does d represent in the formula:

C = π·d

• diameter

• radius

• pi

• 3.14