Download - 10.4 Area of a Circle
Transcript
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Radius The distance from the center of a circle to any point on the circle.
Image: '1917 D penny'www.flickr.com/photos/96586445@N00/188729710
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pi the ratio of the circumference of a circle to its diameter. ( 3.14 )
Image: 'Happy 3.14 Day3'www.flickr.com/photos/17731548@N00/421636858
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Area of a Circle
Area = (pi)(radius)2
A = r2 A = (3.14)r2
3 cmA = (3.14)32
A = 3.14 9A = 28.26 cm2
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Find the area of the key and half circle above the free throw line.
12 ft.
19 ft.
6 ft
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Area of the keyA = bh
A = 19 12 = 228 ft2
Area of the half circleA = r2
A = 3.14 62 = 3.14 36 = 113.04 ft2
We only need the area for half the circle!
113.04 / 2 = 56.52 ft2
Now we need to add them.
228 + 56.52 =
284.52 ft2