Using the Pythagorean Theorem, it is found that the unknown side length of the triangle is of 7.9 cm.
<h3>What is the Pythagorean Theorem?</h3>
The Pythagorean Theorem relates the length of the legs and of a right triangle with the length of the hypotenuse h, according to the following equation:
Researching this problem on the internet, we have that:
The unknown side length is of a leg of x.
The other leg is of 9 cm.
The hypotenuse is of 12 cm.
Hence:
x² + 9² = 12²
x = sqrt(12² - 9²)
x = 7.9 cm.
The unknown side length of the triangle is of 7.9 cm.