In rectangle ABCD, ab = 10cm, ad = 3cm, fold the rectangle along the straight line AC, point B falls at point E, connect De, what is the figure of quadrilateral aced, and explain the reason And calculate its area

In rectangle ABCD, ab = 10cm, ad = 3cm, fold the rectangle along the straight line AC, point B falls at point E, connect De, what is the figure of quadrilateral aced, and explain the reason And calculate its area

First of all, it is obviously isosceles trapezoid. There should be no doubt about it. If you have any questions, you can ask me alone
Now get De
Make DF ⊥ AC in F, eg ⊥ AC in G
Then AF = ad & sup2 / AC = 9 / √ 109
Similarly, GC = 9 / √ 109
So CG = √ 109-2 * 9 / √ 109 = (91 / 109) √ 109
The height is ad * DC / AC = 30 / √ 109
The area is [(91 / 109) √ 109 + √ 109] * 30 / √ 109 / 2 = 3000 / 109