Finding the exact value from goal seek using solve button

[leiarquel]

Hi,
Is there any way that you can solve the exact value of a cell say E9=21.09 using goal seek.
I assigned a button for a macro that solves the value of a E9. The problem is for example I input a value say 5, goal seek will return a value of 0 for E9.
Hope i could assign a restrain say 1>=E9=<E7/2.
Cheers.
link for my file
https://www.dropbox.com/s/9j62rn985xnthtr/Base Plate Support.xlsm?dl=0

 

[leiarquel]

"Hope i could assign a restrain say 1>=E9=<E7/5"