Use the figures to complete the statements proving the converse of the Pythagorean theorem. Drag and drop a phrase, value, or equation into the box to correctly complete the proof. To prove the converse of the Pythagorean theorem, we can define a right triangle, , with sides a, b, and x. Then, we will show that if △ABC is a triangle with sides a, b, and c where a² + b² = c², then it is congruent to △DEF and therefore a right triangle. By the Pythagorean theorem, because △DEF is a right triangle, a² + b² = x². If a² + b² = x² and a² + b² = c² , then c² = x². Further, since sides of triangles are positive, then we can conclude that c = x. Thus, the two triangles have congruent sides and are congruent. If △ABC is congruent to a right triangle, then it must also be a right triangle. Two right triangles with points labeled in capital letters and sides labeled in lower case letters.