Writing C++ program for all of the 3 questions:

a. Write a program that calculates and prints the volume of a sphere given the radius (R) of the circle. The formula to calculate the volume is: Volume = (4/3) * pi * R For the purposes of this problem the value of pi is 3.14159. Enter the radius of the circle: 3 The volume is 113.097 b. Your instructor would like to calculate the average of the class. Write a C++ program that asks the user to enter the marks of three students and prints the average. You may assume that all marks are integers. A sample run of the program is (user input is indicated as bold): AVG CAL ======= Please enter the first mark: 100 Please enter the second mark: 97 Please enter the third mark: 99 The average of the class is: 98.66666667