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