What can I ask on the phone to a Mac user who has a MacBook Pro (Alu), but doesn't know if it's a 15 or a 17 one (and don't have a tool to measure the screen)
What can I ask him to look at to tell me what version it is?
In the left corner of the top menu, pick the apple menu and select
About This Mac.
About This Mac panel, click the
More Info button. if you hover your mouse on
Hardware you can see the general info about your macbook pro such 15" or 17".
As Dori said in comment above solution for before 2007 now choose Graphics/Displays from the left column, it does display the screen resolution.
Might not be that Trivial, but the size between the side of the computer and the keyboard is larger in a 17’’ model:
MacBook Pro 15’’:
MacBook Pro 17’’:
If the user fails to find the information as described above, you can tell him to count the number of holes (no measure required!) ;)