hypot - Euclidean distance function
#include <math.h>
double hypot(double x, double y);
The hypot() function returns the sqrt(x*x + y*y). This is
the length of the hypotenuse of a right-angle triangle
with sides of length x and y, or the distance of the point
(x, y) from the origin.
SVID 3, BSD 4.3
sqrt(3)