Area of Circle
Draw a circle. Divide it into equal (even) sectors and arrange them in line as shown below.
This shape looks like a rectangle of length 'πr' and breath 'r' units
Area of the circle = Area of the rectangle
= length x breadth
= π r x r
= π r2 Sq. units
Area of a circle is πr2 Sq. units
Area of a semicircle = 1/2 πr2 Sq. units
Area of a quadrant = 1/2 πr2 Sq. units.