Circumference and Arc Length

Circumference and Arc Length

By Emily Mcmullan

Circumference of a circle is if you measured the entire edge of a circle.

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It would be like if you took the edge of the circle and laid it flat.​

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Circumference

The Circumference Formula

c = 2π​r

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The formula is c=2(pi)(radius)

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The radius is 12

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So, first input c= 2(pi)(12)

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​​How to do it:

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c= 2(12)(pi)

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c= (24)(Pi)

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c= 75.4​

Multiple Pi Last

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What is Arc Length

Arc Length is a portion of the circumference.

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So the arc length of this bridge is a portion of a whole circle

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We need to know 2 things

1. The central angle measure (How much of the circle are we using)

2. The radius​ (How big is the circle?)

What goes into Arc Length

• What was the central angle?

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• How long was the web

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​Would find how far did he actually swing

Remember that circumference is c=2​πr

Well in arc length when we do Θ​ (the central angle)/360, we're just finding a portion of the circumference.

The Formula

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I just put it all over 360 because it's easier to write.

​​Example!

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Write down the formula for the next slide!​

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How did you do?

If you got it wrong, here's the work

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You had to subtract the given arc measurement by 360

How did you do?

​Practice time!

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Let's try Word Problems

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