Topic 8.5 Circumference

What is the formula to calculate the circumference of a circle?

• 2 * r

• π * r

• 2 * π * r

• π * r^2

Find the circumference of a circle with a radius of 5 units.

• 31.4 units

• 15.7 units

• 62.8 units

• 3.14 units

A circular garden has a circumference of 31.4 meters. What is the radius of the garden?

• 7

• 3

• 5

• 10

True or False: The circumference of a circle is always greater than its diameter.

• True

• Sometimes true, sometimes false

• The circumference and diameter are always equal

• False

If the diameter of a circle is 12 centimeters, what is its circumference?

• 12

• 24

• 48

• 37.7

A circular track has a circumference of 400 meters. What is the diameter of the track?

• 200 meters

• 127.32 meters

• 300 meters

• 500 meters

What is the relationship between the circumference and the diameter of a circle?

• The circumference is half the diameter.

• The circumference is equal to the radius.

• The circumference is equal to the area divided by the radius squared.

• The circumference is equal to pi times the diameter.

Find the circumference of a circle with a diameter of 8 inches.

• 12.56637 inches

• 16 inches

• 25.13274 inches

• 20.28318 inches

A circular swimming pool has a circumference of 62.8 feet. What is the radius of the pool?

• 9.99 feet

• 8.5 feet

• 10 feet

• 12.5 feet

True or False: The circumference of a circle is always a whole number.

• False

• Depends on the size of the circle

• Sometimes

• True