here's my code

```
#include <math.h>
#define M_PI 3.14159265358979323846
// Calculate Constant
double constant()
{
const double figure = 7.9454E-18;
double number = log (figure);
return -10 * number ;
}
```

The value in number should be -17.099... But i get -39.379... What's the problem here?