I don't know. I have a higher Acrobat version installed, and Programs & Features shows a size of 2.5 GB.
That Size information is often an estimate (or plain guess); see http://blogs.msdn.com/b/oldnewthing/archive/2004/07/09/178342.aspx
If you want to know the real size that Acrobat occupies on your disk, right-click on the C:\Program Files (x86)\Adobe\Acrobat 10.0 folder and select Properties; the total size is displayed on the General tab.