In the September 2018 issue of the AARP magazine, the following instructions were given to determine the size of an HD TV that you should buy:
Measure your viewing distance in feet.
Divide by 1.6, then multiply by 12.
That's the optimal screen size in inches.
Convert those instructions into a formula for D in terms of I
where
D = Ideal TV viewing distance in inches
I = Diagonal of your television in inches
Now determine the optimal size HD TV if you sit 8 feet away.
If you bought a 48" TV, how far away should you sit?