Area Circumference and Parts of a Circle

Which formulas can be used to find the circumference of a circle?

• C = π r²

• C = 2π r

• C = π d

• C = 2πd

What number is pi?

• 41

• 00

• 3.14

• 5.14

What is π ? (Best Choice)

• The ratio of the circumference of any circle to its diameter.

• Exactly 3.14

• Exactly 3.1415

• Exactly 3.141593

what is the circumference of this circle ?

• 3.14 cm 

• 37.68 cm

• 24 cm

• 68.4 cm

A Circle has a radius of 4.  What is the area of the circle? (Best Choice) (note: units are squared)

• 4π or about 12.56

• 16π or about 50.24

• 2π or about 6.28

• 8π or about 25.12

A Circle has a diameter of 10 centimeters.  What is the area of the circle? (Best Choice)

• 5π or about 15.7 cm²

• 10π or about 31.4 cm²

• 25π or about 78.5 cm²

• 100π or about 314 cm² 

The circumference of a circle is

• The measurement from an edge of a circle to another edge.

• The measurement around the circle

• The measurement from an edge of a circle to another edge going through the center

• The measurement from the center of the circle to an edge of the circle

What is the distance around a circle?

• Circumference

• Area

• Diameter

• Radius

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

• Radius

• Diameter

If my radius is 10ft, what is my diameter?

• 20ft

• 5ft

• 31.4ft

• 62.8ft