What size traditional TV would have the same viewing area (number of square inches) as a 60" HDTV?
The screen aspect ratio, that is, the ratio of the horizontal length of a TV screen to
its vertical height, is 16 : 9 for HD TVs and 4 : 3 for traditional televisions.
The "inch size" of the TV always refers to the diagonal measurement of the TV,
so a 60" TV would be the diagonal measurement.