$\"\"$

Pythagorean theorem states that, If a triangle is a right triangle, then the sum of the squares of the lengths of the legs a and b equals the square of the length of the hypotenuse c.

The expression is: $\"\"$

$\"\"$

$\"\"$ (Substitute $\"\"$ )

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

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

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

$\"\"$ (Square root: $\"\"$ ) $\"\"$

The length of hypotenuse is 10cm.