The 5th Annual China PHP Conference


(PHP 4 >= 4.1.0, PHP 5, PHP 7)

hypot Calculate the length of the hypotenuse of a right-angle triangle


float hypot ( float $x , float $y )

hypot() returns 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. This is equivalent to sqrt(x*x + y*y).



Length of first side


Length of second side

Return Values

Calculated length of the hypotenuse

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User Contributed Notes 1 note

robinv at ecosse dot net
13 years ago
A simpler approach would be to allow an arbitrary number of parameters. That would allow for whatever number of dimensions you want *and* it would be backwards compatible with the current implementation.


function hypo()
$sum = 0;
    foreach (
func_get_args() as $dimension) {
        if (!
is_numeric($dimension)) return -1;
$sum += pow($dimension, 2);

hypo();          // vector in 0 dimensions, magnitude = 0.
print hypo(1);         // vector in 1 dimension,  magnitude = 1.
print hypo(3, 4);       // vector in 2 dimensions, magnitude = 5.
print hypo(2, 3, 6);     // vector in 3 dimensions, magnitude = 7.

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