Circumference of Circles

Circumference of Circles

Wednesday 2/3/21

Today, we will focus on finding the circumference of a circle. Circumference is the distance around a circle (like perimeter), so it is measure in units such as "inches", "feet", "centimeters", etc.

NOT square units!

Unlike area, there are two formulas that can be used to find the circumference of a circle:

One when given the diameter

and

One when given the radius.

Continue clicking through the next slides to view an example on finding the circumference of a circle when given the radius.

After the guided example, you will try one on your own!

Now, you will try one on your own!

Fill in the Blank

Find the circumference of the circle.

Type your answer as _____ m

Sample: 3.14 m

Now, continue clicking through the next slides to view an example on finding the circumference of a circle when given the diameter.

After the guided example, you will try one on your own!

Now, you will try one on your own!

Fill in the Blank

Find the circumference of the circle.

Type your answer as _____ ft

Sample: 3.14 ft

Now try these last few problems as the remainder of your classwork. We will continue practicing tomorrow!

Copy down the two formulas if you haven't already:

 $C=\pi d$  and  $C=2\pi r$  

Fill in the Blank

Find the circumference of the circle.

Type your answer as _____ ft

Sample: 3.14 ft

Fill in the Blank

Find the circumference of the circle.

Type your answer as _____ in

Sample: 3.14 in

In this last one, you will need to work backwards, since you are given the circumference and will need to find the diameter. Use the most appropriate formula, substitute in what you know, and solve for what is missing.

Fill in the Blank

A circle has a circumference of 109.9 feet. What is its diameter?

Type your answer as _____ ft

Sample: 3.14 ft