We bought a new 50" TV this week. The kids said they didn't see any difference between it and the old 37". So how much bigger is it?

TVs have always been measured along the diagnoal. This gives the marketers the largest possible number to advertise.

Modern HD screens have an aspect ratio of 16:9, that is for every 16 units wide the screen is, it's 9 units high. (old analog TVs were 4:3).

So some algebra later, we find that to get the height of an HD screen, multiply the diagonal by 0.49. To get the width, multiply the diagonal by 0.87.

To get the area, multiply width by height, or to save a step, square the diagonal size and multiply by 0.4263.

So the 37" screen has and area of about 583 square inches, the new 50" is about 1065.75 square inches, or 180% the size.

Don't know how much larger it has to be for kids to notice.