area of a circle
Post on 31-May-2015
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WELCOME
CIRCULAR MEASURES
By Nazirin Banu
CIRCLE
O r
AREA OF A CIRCLE
Draw regular polygons with more and more sides with in the circle , their areas would get
closer and closer to the area of the circle.
By joining the vertices of the polygon to the center of the circle , we can divide the polygon into triangle
If the polygon has n sides, then its area is :n*(1/2)sh= (1/2)nsh
‘ns ’ i s the sum of a l l s ides of the polygon
In other words ns is perimeterPerimeter denoted by p
Area of the polygon = (1/2)ph
Increase the number of sides , the polygon gets closer and closer to the circle . The perimeter and
area of the polygon get closer and closer to the perimeter and area of the circle
Area of the circle = (1/2)*perimeter of the circle * radius = (1/2)*2∏*radius*radius = ∏*square of radius
END
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