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<overview>

<p>

Calculating the length of the hypotenuse using the standard formula <code>c = sqrt(a**2 + b**2)</code> may lead to overflow if the two other sides are both very large.

Even though <code>c</code> will not be much bigger than <code>max(a, b)</code>, either <code>a**2</code> or <code>b**2</code> (or both) will.

Thus, the calculation could overflow, even though the result is well within representable range.

</p>

</overview>

<recommendation>

<p>

Rather than <code>sqrt(a**2 + b**2)</code>, use the built-in function <code>hypot(a,b)</code> from the <code>math</code> library.

</p>

</recommendation>

<example>

<p>

The following code shows two different ways of computing the hypotenuse.

The first is a direct rewrite of the Pythagorean theorem, the second uses the built-in function.

</p>

<sample src="Pythagorean.py" />

</example>

<references>

<li>Python Language Reference: <a href="https://docs.python.org/library/math.html#math.hypot">The hypot function</a></li>

<li>Wikipedia: <a href="https://en.wikipedia.org/wiki/Hypot">Hypot</a>.</li>

</references>

</qhelp>