Use Object Snaps
 
 
 

To set running object snaps

  1. Click Tools menu Drafting Settings.At the Command prompt, enter dsettings.
  2. In the Drafting Settings dialog box, Object Snap tab, select the object snaps you want to use.
  3. Click OK.
 Toolbar: Object Snap 
 Command entry: OSNAP
 Shortcut menu: Hold down SHIFT and right-click to display the object snap menu. Click Osnap Settings.