BELL RINGER

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BELL RINGER
104º
89
90
x
x
Find x.
Find x.
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Determining the Area and Circumference of a Circle

• What is p ??
• Its actual value is 3.14159 . . .
• It never stops, the train of numbers continues to
  infinity.
• How do you get this decimal? Observe the
  sketchpad example.

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More about p

• p circumference
• diameter
• The distance around the circle (perimeter) is
  circumference.
• The distance across the circle is diameter.

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Circumference and Area

• Circumference 2p r dp
• Area p r2

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Example,

• A goat is tied to a stake with a 15 foot rope.
  What is the total area of grass that the goat may
  roam? What is the distance around the area in
  which the goat can reach?
• Acircle p r2 p (152) 225p
• Circumference 2p r 2p 15 30p

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Classwork

• P.334, 10-15, 19