The formula for a circle's area is pi*radius*radius.
The diameter is equal to two times the radius.
D = 2*radius
So, the radius is 4.5 cm
Area = pi*radius*radius = 3.14159 * 4.5cm * 4.5cm = 63.617 cm2
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The area of a circle with a radius of nine centimeters is: 254.5 cm2
3.14
Exact area of the circle: 9*pi inches
The area is 63.617 dm2
Exact area of the circle: 9*pi inches