What is the (x) length of a triangle if leg 1 equals 5 and the hypotenuse equals 13

Wow this will be late. Surprised no one answered this when it was on the regular list.

Pythagorean Theorem states a² + b² = c² where the sum of the squares of the two legs of a triangle (a and b) are equal to the square of the hypotenuse (c).

5² + b² = 13²

25 + b² = 169

b² = 144

b = 12

The length of the unknown leg labeled x is 12 units.