Exercise 8 Page 719

Let's begin with recalling the formula for the circumference of a circle. C=π dIn our exercise we are given that the circumference of the circular swimming pool is about 56.5 feet. To find the diameter of the pool we will substitute 56.5 for C into above formula and solve for d.

The diameter of the swimming pool is approximately 17.98 feet. Next we can use the fact that the radius is half of the diameter. r=1/2* 17.98=8.99 The radius of the swimming pool is approximately 8.99 feet.

Extra

Segments in Circles

Let's review what we know about different segments that intersect a circle. We will use the graph below as an example.

Now let's take a look at the different types of segments in circles and their definitions.

Pairs of Angles
Type	Definition	Example
Chord	A straight line that goes from one point to another point on the circle.	AC
Radius	Connects the center of the circle and any point on the circle.	DO
Diameter	Both endpoints of this segment lie on the circle and it passes through the center.	AB