Final answer:
Triangle JKL is proved to be a right triangle by demonstrating that it has side lengths that satisfy the Pythagorean theorem a² + b² = c². Because triangle DEF is a given right triangle with the same side lengths that satisfy the theorem, triangle JKL must also be a right triangle.
Step-by-step explanation:
To prove that triangle JKL is a right triangle, we must demonstrate that one of its angles is a right angle. Since triangle DEF is given to be a right triangle, we apply the Pythagorean theorem, which establishes that if a triangle has sides of length a, b, and c, with c being the hypotenuse, the relationship a² + b² = c² is satisfied.
We already know that a² + b² = c² for triangle JKL. These two equations confirm that triangle DEF and triangle JKL have side lengths that satisfy the Pythagorean theorem. Because we know triangle DEF is a right triangle and triangle JKL satisfies this necessary condition of right triangles, it follows that triangle JKL must also be a right triangle by the Converse of the Pythagorean theorem.
Therefore, since both triangles satisfy a² + b² = c² and triangle DEF is a right triangle by definition, we can conclude that triangle JKL is also a right triangle. This is because it satisfies the necessary condition for a triangle to be classified as a right triangle, and therefore triangles DEF and JKL are congruent in terms of side lengths and right angles, making triangle JKL a right triangle.