how to find out the area of a circle- c programming example

The area of the circle is defined as A = π . R2, having π as 3.14159. Calculate the area using the formula given in the problem description. Input *************************************************************************************************************************** Read the variable R (double precision), that is the radius of the circle.print endline. Output ************************************************************************************************************************* Print the variable A, rounded to four decimal digits. Sample Inputs Sample Outputs 2.00 A=12.5664 100.64 A=31819.3103 150.00 A=70685.7750