Write down C# program which inputs radius of a circle and outputs its area. Permit the user to repeat computations as often as desired. Use Math.PI for value of pi. Area of a circle is pi times square of the radius

Write down a C# program to make change. Enter cost of item which is less than one dollar. Output coins given as change, by using quarters, dimes, nickels, and pennies. Use fewest coins possible. For instance, if item cost 17 cents, change would be three quarters, one nickel, and three pennies.