I found the answer after playing with the math. The problem was Illustrator doesn't deal with inches only points hence the (w/72) (h/72) portion when it gets the size. 72 points = 1 inch so the math had to convert points to inches. like so
tell application "Adobe Illustrator"
activate
tell document 1
--get current size
set tempGroup to make new group item with properties {name:"TempGroup"} -- Create a temporary container group
duplicate every page item to beginning of group item "TempGroup" -- copy instances to it
set {w, h} to {width, height} of tempGroup -- get properties
delete tempGroup
display dialog "Width of Art: " & (w / 72) & return & "Height of Art: " & (h / 72)
--resize
set newWidth to text returned of (display dialog "Please enter Art Width:" default answer "10")
set artWidth to width of tempGroup
set sum to (artWidth / newWidth * 100)
set scalePercentage to (72 / sum * 10000)
scale tempGroup horizontal scale scalePercentage vertical scale scalePercentage
end tell
end tell
end