Can these measures be the side lengths of a triangle 6in5in11in?

No, the measures 6 inches, 5 inches, and 11 inches cannot be the side lengths of a triangle. According to the triangle inequality theorem, the sum of the lengths of any two sides must be greater than the length of the third side. In this case, 6 + 5 = 11, which is not greater than 11, thus failing the triangle inequality condition.