The distance around the outside of a polygon is called the perimeter.
The distance around the outside of a circle is called the _______________.
We should recall that that diameter of a circle is a chord that _____________ ______________.
Circumference Conjecture
If C is the circumference of a circle and d is the diameter of the circle, then there is a number π such that C = ____. Since d = 2r, where r is the radius, then you can also say C = ______. 1
Example:
If a circle has a diameter of 3m, find its circumference and its radius.
Example:
If a circle has a circumference of 12π meters, what is its diameter? Its radius?
2
Use the circumference conjecture to solve the following. Leave your answer in terms of π. 3
4