$\"\"$

The side lengths of a right triangle are $\"\"$ ; $\"c$ .

Apply Pythagorean theorem: $\"a$

$\"\"$ (Substitute 5 for a and 3 for b)

$\"\"$ (Evaluate powers: $\"\"$ ) $\"\"$

$\"\"$ (Add: $\"\"$ )

$\"\"$ (Take square root each side)

$\"\"$ (Cancel sqaure and root) $\"\"$

The unknown length of $\"\"$ .