1 The crossing point B is the vertical line of CD, and the vertical foot E CD-AB=6 6/2=3, that is, CE=3, then BE= radical sign.

Lower (5 2-3 2) = 4, so the height of the trapezoid is 4.

2 Let the width be x and the length be X+5.8.

(X+X+5.8)* 2 = 68.4 X = 14.2S = X *(X+5.8)= 14.2 * 20 = 284

3 let the bottom be x and the top be X+3.4.

(x+x+3.4) * 5.8/2 = 36.54x = 4.6cm.

4 is the waist, AB, CD, AD and BC are the upper and lower bottoms. Because the diagonals of AC and BD are equal, the quadrilateral ABCD is an isosceles trapezoid.