CHAPTER 11.4 CIRCUMFERENCE and ARC LENGHT
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Transcript of CHAPTER 11.4 CIRCUMFERENCE and ARC LENGHT
CHAPTER 11.4CIRCUMFERENCE and ARC LENGHT
Stephan Schutt, Vanessa Jo, Quique DegenhartIsabel Mendez and Guiselle Roesch
Circucumference The circumference of a circle is the distance
around the outer part or a circle. It can also be called the area of a circle.
The ratio (π= 3.14) of the circumference to the Diameter is the same for all the circles.
Examples…
The Circumference of a circle is πD or 2πR.
C=πdC=3.14 X DC=3.14X10C=31.4 cm.
C=2πrC=2(3.14 X 5)C=31.4 cm.
5 cm
10 in.
C= 2πrC= 2(3.14 x 10)C= 62.8 in.
4 cm.
C=2πrC=2(3.14 x 4)C= 25.12 cm.
Arc length…
It is a side/part of the circumference of a circle. The measure of the arc may be used (in degrees) to find its length.
Arc
Arc Length Corollary…
Is the ratio of the arc length to the whole measurement of the circle, which is 360°
Arc length m AB 2πr 360° or you can also use: m AB
Arc length of AB = 360°
A
B
360°
How to do the Arc Length Corollary…
P
A
B
X7
50°
Arc length m AB 2πr 360° =
X 50°2π7 360° =
X 50°43.96 360° =
43.96 x 50= m ÷ 360
X≈6.1
Examples…
7 cm
500
Arc length of LM = 50/360 x 2π(7)= 6.10
L
M
5 cm.
52o
Arc length of AB= 52/360 x 2π(5)= 4.53
6cm
45
Arc length of IJ= 45/360 x 2π(6)= 4.71
Practice
Individualy solve the problems as soon as you have the answer and come up to the board if you have it right you will win a candy.