You can try to bruteforce it out and just increment by 0.01 maybe that will work out.
But the answer wouldnt be exact.
So u can try in for an approx val.
Then test it up. If the value you got. is squared is lesser than the main number of which you should find the square root then increment. But if the the square of the value increases take the previous number as the approximate square root. So you will only be missing the minutest details
For Each ctrl As Control In Me.Controls("pnlMainPanel").Controls
If ctrl.GetType Is GetType(System.Windows.Forms.Panel) Then
For Each subCtrl As Control In ctrl.Controls
If subCtrl.GetType Is GetType(System.Windows.Forms.TextBox) Then
If subCtrl.GetType Is ...