Create a float variable named diameter. This variable will hold the diameter of a circle. d. Create a float variable named PI.

float diameter=2*r; / /hold the diameter of a circle

float PI; / / float variable named PI.

Explanation:

Here we have declared two variable i. e diameter and PI of type float. The variable diameter will hold the diameter of a circle i. e 2*r where r is the radius of a circle.

Following are the program in c++

#include / / header file

using namespace std; / / namespace

int main () / / main function

{

float r=9.2; / / variable declaration

float diameter=2*r; / /hold the diameter of a circle

float PI=3.14; / / float variable named PI hold 3.14

cout<<"diameter IS : "<
return 0;

}

Output:

diameter IS : 18.4

PI IS : 3.14