That is to say, the point DE is vertical.
Triangle QFE, triangle EDA and triangle DGP are all similar (congruence angle formed by right angle and parallel line).
Because PD: QE = 9: 4
According to the similarity, GP: EF = 9: 4 (the similarity between triangle QFE and triangle DGP) can be obtained.
Let gp = 9k and ef = 4k.
The coordinates of ABCDE5 point are expressed by ef, and the shadow area is also expressed by K.
Then the equation is composed of EA:DG=DA:PG.
Available k 4 = 1/36
That is, k 2 = 1/6.
Then bring it into the calculation = 13/3.