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McGraw Hill Integrated II, 2012

MH

McGraw Hill Integrated II, 2012 View details

1. Circles and Circumference

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Exercise 22 Page 720

Recall that the circumference of a circle is the product of its diameter and pi.

Radius: 8 inches
Circumference: 50.27 inches

Practice makes perfect

We are given that a pizza has a diameter of 16 inches and asked to evaluate the radius r and the circumference. First let's recall that the radius is the half of the diameter. r=1/2* 16=8This means that the radius of the pizza is 8 inches. Next let's recall the formula for the circumference of a circle. C=π d By substituting 16 for d in above formula we can find the circumference of the pizza. We will round the result to the nearest hundredth.

C=π d

d= 16

C=π ( 16)

Multiply

C=50.2654...

Round to 2 decimal place(s)

C≈ 50.27

The circumference of the pizza is approximately 50.27 inches.

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

Subchapter links

Exercises p.719-723