OpenSAT

Triangle \(ABC\) is a right triangle, so we can use the Pythagorean Theorem: \(a^2 + b^2 = c^2\), where \(a\) and \(b\) are the lengths of the legs and \(c\) is the length of the hypotenuse. In this case, \(AB = 5\) and \(AC = 12\), so \(BC\) is the hypotenuse. Substituting into the Pythagorean Theorem, we get \(5^2 + 12^2 = BC^2\), or \(169 = BC^2\). Taking the square root of both sides gives \(BC = 13\).