Circles, Circles, Circles!

A line segment that goes from the center to the edge of a circle.

• Diameter

• Radius

• Circumference

• 

  $\pi$

Which of the following shows a formula for finding the circumference of a circle?

• $C\ =\ \pi d$

• $C\ =\ \pi r^2$

• $C\ =\ \frac{1}{2}r\pi$

• $C\ =\ 3d$

Which of the following shows a formula for finding the circumference of a circle?

• $C\ =\ 2\pi r$

• $C\ =\ \pi r^2$

• $C\ =\ \frac{1}{2}r\pi$

• $C\ =\ 3d$

A line segment that goes from one edge of a circle to the other and passes through the center.

• Radius

• Diameter

• Circumference

• Area

The distance around the circle.

• Radius

• Diameter

• Circumference

• Area

What is the radius of the circle pictured?

• 20

• 10

• 40

• 3.14

Given the circle. What is the diameter?

• 100

• 25

• 3.14

• 250

Radius = 4, what's the exact value for the circumference?

• $4\pi$

• $8\pi$

• $16\pi$

• $3.14\pi$

Diameter = 3, what's the exact value for the circumference?

•  $6\pi$ 

•  $9\pi$ 

•  $3\pi$ 

• $3.14\pi$

A figure where all points are the same distance to a point called the center.

• Square

• Triangle

• Circle

• Rectangle