When a triangle is rotated 180 degrees about a point, the lengths of the sides of the triangle do not change. The triangle's dimensions remain the same regardless of the rotation.
In your case, the right triangle has side lengths of 5 inches, 12 inches, and 13 inches. The longest side of the triangle is 13 inches.
Therefore, after the triangle is rotated 180 degrees, the length of the longest side will still be 13 inches.