#include <iostream>
#include <cmath>
int main()
{
constdouble PI = 3.14159265359; //Defines a constant PI, which will always be equal to 3.14159265359.
double v = 0, area; //Declare some doubles.
while(v <= 0) //While v has a value less than or equal to zero, get user input.
{
std::cout << "Enter variable: ";
std::cin >> v;
}
area = 0.071 * (pow(v,3) / sqrt(9) * PI); //Pow --> Raises x to the power y. pow(x,y). //sqrt(x) finds square root of x.
std::cout << "\nAnswer: " << area; //Output the answer.
return 0;
}