hi. When your defining your values, do it before int main()

also the correct syntax is define M2F 3.208

there is no semi-colon

#include <stdio.h>
#include <math.h>

/* the given dimensions of the tank in meters*/
#define DIAMETER 5.0
#define HEIGHT 10.0
/* conversion factors*/
#define M2F 3.2808
#define F2G 7.481
int main()...