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

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

The definition of radius is

• distance from one point to another point

• distance around the circle

• distance from the center to any point on the circle

• distance across the circle through the center

what is the formula for finding diameter

• r = 2 d

• d = 2 r

• a = m c²

• c = π 2 r

what is the formula for finding circumference

select ALL that apply

• c = π d

• c = 2 π r

• d = 2 r

• r = d/2

Find the radius of the circle

• 20 ft

• 10 ft

• 5.5 ft

• 10

what is the formula for finding area of a circle

• C = π r²

• A = π r²

• A = π r² / 2

• C = 2 π r

If the area of circle is 100 π , find the radius of the circle.

• 10 π
• 10
• 50
• 50 π