3. (Diameter, Circumference and Area of a Circle) In this chapter, you have learned about int. C# can also represent floating-point numbers points, such as 3.1415926. Write a C# program that accepts the value of a variable (the type int and representing the radius of a circle), then calculates the circle's diameter, circumference and area, and outputs the values of the circle's diameter, circumference and area. When writing the program, the formulas need are listed below: (r is the radius): diameter 2r circumference 2TTr area TTr2 The type of TT is double and the value is 3.1415926. (20 points)