Circle Formula

Which formula can be used to find the length of the secants in the diagram?

• a∙b=c∙d

• outside∙whole=outside∙whole

• angle = 1/2(arc + arc)

• angle = 1/2(big - small)

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

Which formula would help you solve the following problem: A circle has a diameter of 7.6 feet. What is the circumference of the circle in feet?

What two formulas can you use to find the circumference?

• C = π·d

• C = π·r²

• C = 2·π·r

• C = d²

The radius of the circle is 9 meters.  What is the circle's circumference?

• 9 meters

• 28.26 meters

• 56.52 meters

• 18 meters

find the area of the circle with radius 3 cm below.

• 100 cm²

• 225 cm²

• 9 cm²

• 28.26 cm²

A circular swimming pool is 21 feet in diameter. Which formula below will help you determine the circumference of the pool?

Determine the formula needed to solve the following question:

Chloe has a round pillow with a diameter of 17 in. What is the area of her pillow?

The distance around a circle is

• Circumference

• Radius

• Center

• Central Angle

The distance from a circle to its center

• Chord

• Central angle

• circumference

• radius