As shown in the figure, the quadrilateral ABCD is a rectangle, AB: ad = 4:3, fold the rectangle along the straight line AC, point B falls at point E, and connect De, then de: AC = 1___ ．

Let AB = 4K, ad = 3k, then AC = 5K. From the area of △ AEC = 4K × 3K = 5K × eh, eh = 125k; according to Pythagorean theorem, ch = ec2-eh2 = 9k2 - (125k) 2 = 95k, ∵ quadrilateral aced is isosceles trapezoid, ∵ ch = AF = 95k, so de = 5k-95k × 2 = 7k5

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1. 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
2. As shown in the figure, the quadrilateral ABCD is a rectangle, ab = 4AD = 3, fold the rectangle along the straight line AC, point B falls at point E, connect De, what is the figure of quadrilateral aced What about perimeter and area
3. Rectangle ABCD is discounted along diagonal, ab = 4, ad = 3, what is quadrilateral aced Area is also required
4. As shown in the figure, fold the rectangular piece of paper ABCD, first fold out the crease BD, and then fold so that the ad side coincides with the diagonal BD, and get the crease dg. if AB = 2, BC = 1, then the length of Ag is___ ．
5. As shown in the figure, in rectangular paper ABCD, ab = 4, ad = 3, fold the paper so that the ad side coincides with the diagonal BD, and the crease is DG, then the length of Ag is () A. 1B. 43C. 32D. 2
6. As shown in the figure, fold the rectangular piece of paper ABCD, first fold the crease (diagonal) BD, and then fold so that the ad edge coincides with BD, and get the crease DG, if AB = 4, BC = 3, find the length of Ag
7. As shown in the figure, fold the rectangular piece of paper ABCD, first fold out the crease BD, and then fold so that the ad side coincides with the diagonal BD, and get the crease dg. if AB = 2, BC = 1, then the length of Ag is___ ．
8. As shown in the figure, in rectangular ABCD, fold △ ABC along AC to △ AEC position, CE and ad intersect at point F. (1) try to explain: AF = FC; (2) if AB = 3, BC = 4, find the length of AF
9. In rectangle ABCD, ad = 3. BC = 4. If the rectangle is folded along the diagonal BD, what is the shadow area in the figure?
10. If the median line on the two right sides of a right triangle is 5cm and 2 √ 10cm respectively, the length of the oblique side is Such as the title
11. Quadrilateral ABCD is a rectangle, ab = 4cm, ad = 3cm, fold the rectangle along the straight line AC, and point B falls at e to connect de. what is the figure of quadrilateral aced? What's its area? What's its perimeter?
12. As shown in the figure, the quadrilateral ABCD is a rectangle, ad = 3, ab = 4. Fold the rectangle along the line AC, point B falls at point E, and connect De, then the length of De is () A. 1B. 95C. 725D. 75
13. As shown in the figure, e and F are the points on the diagonal AC and BD of rectangular ABCD, and AE = DF
14. As shown in the figure, fold the rectangular piece of paper ABCD along the diagonal AC, so that point B falls at point E. verify: EF = DF
15. In rectangle ABCD, ab = 10, BC = 8, fold the rectangle along AC, point d falls at point E, and CE and ab intersect at point F, then the length of AF is
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