I had bought 2 screens, both 19-inche.

One is Normal and another is widescreen. I only want to prove that which one has more viewable areas (by Theory).

Normal screen has ratio of wide and height at 4:3 and wide screen 16:9; So if we want to compare easier then change 4:3 to 16:12.

So the diagonal line can be calculated as

                                                                                               a2 + b2 = c2 While a = width; b=height and c=diagonal;

thus that:

Normal one will have a coefficient as “A” and wide one will define as “B”

then

                                                                                                Normal:   (12A)2  + (16A)2  = 192  
                                                                                                Wide:      (9B)2  + (16B)2  = 192   

and then

A2 = 361/400 and B2 = 361/337

                                                                                               A = 19/20  and  B = 19/18.358 
                                                                                              Area = a x b

Then

                                                                                                normal: (12 x 19/20) x (16 x 19/20) =  173.28 in2 

and

                                                                                                wide:    (9 x 19/18.358) x (16 x 19/18.358) =  154.25 in2 

So wide screen has less space than normal one. * *