Circumference is the distance around a circle. The circumference can also be called the perimeter of a circle. However, we use the term circumference for circles because they are round.
What if you were given the radius or diameter of a circle? How could you find the distance around that circle?
Find the circumference of a circle with a radius of 7 cm.
Plug the radius into the formula.
Find the perimeter of the square in Example 3. Is it more or less than the circumference of the circle? Why?
The tires on a compact car are 18 inches in diameter. How far does the car travel after the tires turn once? How far does the car travel after 2500 rotations of the tires?
- Find the circumference of a circle with
- Find the length of the diameter of
- How does the diameter relate to
- Find the perimeter of
- Find the circumference of
For questions 14-17, a truck has tires with a 26 in diameter.
- How far does the truck travel every time a tire turns exactly once? What is this the same as?
- How many times will the tire turn after the truck travels 1 mile? (1 mile = 5280 feet)
- The truck has travelled 4072 tire rotations. How many miles is this?
- The average recommendation for the life of a tire is 30,000 miles. How many rotations is this?
To see the Review answers, open this PDF file and look for section 10.8.