Answer:

Step-by-step explanation:
= 
2*(pq)= 2(
)= 
-3
= -3
= 
=
=

First, let's list the lengths of the sides in descending order.
Lengths of sides of quadrilateral ABCD: 20, 18, 14, a
Lengths of sides of quadrilateral EFGH: b, c, 6, 5
From the listings above, we see that he sides measuring 14 and 6 are corresponding.
We are looking for c which corresponds to 18.
14 is to 6 is as 18 is to c
14/6 = 18/c
7/3 = 18/c
7c = 3 * 18
7c = 54
c = 54/7 = 7 5/7
Answer: 7 5/7 feet