Answer:
x = 5.
Step-by-step explanation:
For a right triangle, use the Pythagorean Theorem, a² + b² = c², where a and b are the sides, and c is the hypotenuse.
a² + b² = c²
x²+ 12² = 13²
x² + 144 = 169
Subtract 144 from both sides.
x² = 25
x = 5.
Proof:
a² + b² = c²
5² + 12² = 13²
25 + 144 = 169
169 = 169.
