In ▱ ABCD, it is known that ab = 2ad and M is the midpoint of ab. please confirm the position relationship between DM and MC and explain the reason

In ▱ ABCD, it is known that ab = 2ad and M is the midpoint of ab. please confirm the position relationship between DM and MC and explain the reason

It is proved that DM and MC are perpendicular to each other, ∵ m is the midpoint of AB, ∵ AB = 2am, ∵ AB = 2ad, ∵ am = ad, ∵ ADM = ∠ AMD, ∵ ABCD, ∵ ab ‖ CD, ∵ amd = ∠ MDC, ∵ ADM = ∠ MDC, i.e. ∵ MDC = 12 ∠ ADC, similarly, ∵ MCD = 12 ∠ BCD, ? ABCD, ∥ ad ‖ BC, ∥ MDC + M

As shown in the figure, e and F are any points of AB and ad of parallelogram ABCD respectively. Please explain the area relationship between triangle BCF and triangle ECD

Equal
It is proved that because s △ BCF = 1 / 2H * BC, s △ ECD = 1 / 2H '* CD,
Because the area of parallelogram ABCD is s = h * BC = H '* CD,
Then s △ BCF = 1 / 2S = s △ ECD,
So the area of triangle BCF and triangle ECD are equal

As shown in the figure, e and F are the points on the sides AD and ab of the parallelogram ABCD respectively, then the triangle with equal area is ()
A. Delta CDE and delta BAE
B. Delta DAF and delta CBE B. deltadaf and delta CBE
C. The relationship between △ EBC and △ ECD
D. Delta EBC and delta DBC

D. Delta EBC and delta DBC
The area of the two triangles is half that of the parallel polygon