Other people referred to it, but to state it clearly, TVs are measured from the corners of the picture while monitors are measured from the corners of the tube.

They might be in the US. In the UK TVs are also measured from the corners of the tube, my 32" screen has a 29.5" viewable area.

For example if you take a look at:

http://products.sony.co.uk/productdetail.asp?id=2_1_2573

You will see Sony taking about their KD36NX200 36" TV which has a 34.6" visible area.
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