Lesson 4A.10 - 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 circumference of a circle is 22 π ft, what is the radius?

• 22 ft
• 11ft
• π ft
• no ft

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

• 10 in
• 5 in
• 25 in
• pi in

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

If you are given the diameter, how can you calculate the radius?

• Multiply the diameter by 2
• Divide the diameter by 2
• Add 2 to the diameter
• Subtract 2 from the diameter

Which segment is the diameter?

• AC
• BD
• LM
• CE

Which segment is a radius?

• LM
• DC
• BD
• ML

Find the radius of the circle

• 20 ft

• 10 ft

• 5.5 ft

• 10

Find the area of the circle, round to the nearest hundredths place.

• 43.96

• 153.86

• 87.82

• 307.72