Circles Day

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

• 10 in

• 5 in

• 25 in

• pi in

If the circumference of a circle ( in terms of Pi) is 22 π ft, what is the radius?

• 22 ft

• 11ft

• π ft

• no ft

If the circumference of a circle is 44 π feet, what is the radius?

• 22 ft
• 44 ft
• 33 feet
• 3.14 feet

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

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

• 10 π
• 10
• 50
• 50 π

What is the circumference? Use 3.14 for pi.

• 50.24

• 25.12

• 24.5

• 18.3

Find the area of the circle. Leave in terms of π.

• 18π in²

• 9π in²

• 81π in²

The diameter of the circle is 6 inches. What is the circumference? Leave in terms of π.

• 6π in

• 12π in

• 36π in

• 24π in