Friday, April 9, 2010

How to find area of a circle

The circle is a plane curve all points of which are equidistant from a point in the plane called the center. The area of a circle is equal to the product of the circumference and the diameter divided by 4. Diameter is equal to twice that of radius. So area of a circle can be calculated by the equation, Area= pie * square of the radius. The value of pie=22/7. I will show you how to find the area of a circle using an example.
  • Consider a circle of radius 10 cm and circumference of 62.8cm.
  • Substitute the values in any of the two equations, A= (Cd)/4 or A= pie * square of radius. 
NOTE: Here, A is the area of circle, C is the circumference of the circle, d is the diameter of the circle and pie= 22/7.
By substituting values in first equation, 
   A= (62.8*2*10)/4.
   Thus Area of the circle of radius 10 cm and circumference of 62.8 cm is 314 sq.cm.

By substituting values in second equation,
   A= pie * sq.radius.
   A= (22/7) * 100. Thus area of circle is 314 sq.cm.

Thus you can find the area of a circle if the diameter and circumference or radius is known.

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