Concepts on Circles

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

• C = π r
• C = 2 π r
• C = π d
• C = 2 π d

If the area of a circle is 25 π in² , then what is the length of the diameter?

• 10 in

• 5 in

• 25 in

• pi in

If the circumference of a circle is 22 π ft, what is the radius?

• 22 ft
• 11ft
• π ft
• no ft

The _____ is the distance from the center to any point on the circle.

• diameter
• radius
• π
• center

The distance across a circle through its center is called the _____.

• diameter
• radius
• π
• center

A _____ is half of a circle.

• circumference
• pi
• semicircle
•  composite figure

Which segment is the diameter?

• segment AC

• segment BD

• segment LM

• segment CE

Which segment is a radius?

• segment LM

• segment DC

• segment BD

• segment AL

The definition of a circle is

• set of all points in a plane that have the same distance from a fixed point called the center

• the union of two non-collinear rays with a common endpoint

• a figure with equal angles and equal sides

• a pizza, orange, plum, or watermelon

The definition of circumference is

• distance from the center of any point on the circle

• distance from one point to another

• distance around the circle

• distance from the center of any point on the circle