Solution: A classmate's judgment is correct. △MDE is always an isosceles right triangle. As shown in the figure: connecting CM, ∵M is the midpoint of hypotenuse AB, ∴ cm ⊥ AB, and the bisector of cm ∠ ACB is the "three lines in one" of isosceles triangle), ∴∠ DMC = ∠ EMA ∠∠ A ≈.

Student B's judgment is correct. The area of the quadrangle MDCE is always equal to half the area of △ABC, so it is a fixed value of 4.

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