How Do You Estimate the Physical Dimensions of a 65-Inch Television?

Determining the dimensions of a 65-inch television requires knowing whether it is an SDTV or an HDTV. An SDTV has an aspect ratio of 4:3, yielding a 52-by-39-inch screen. An HDTV's aspect ratio is 16:9, providing a screen size of 56.55 by 31.85 inches.

Calculating the screen size of a television set requires using the Pythagorean theorem for right triangles. The measurement used for describing a television is the diagonal length of the screen. The two most common screen formats, SDTV or HDTV, have aspect ratios of 4:3 and 16:9, respectively. Given this, SDTV screen measurements are 0.8 times the diagonal for the width and 0.6 for the height; HDTV screens are 0.87 times the diagonal wide and 0.49 times the diagonal for the height.