Mathematical calculation 123 As shown in the figure, M is a moving point on ad in the parallelogram ABCD to know that the area of the parallelogram ABCD is a, so does the area of the triangle MBC change? Why?

Mathematical calculation 123 As shown in the figure, M is a moving point on ad in the parallelogram ABCD to know that the area of the parallelogram ABCD is a, so does the area of the triangle MBC change? Why?

It should be kept at a / 2
Because the bottom edge is BC unchanged and BC / / AD, the size of height remains unchanged, the bottom edge and height remain unchanged, and the area remains unchanged