120 inch refers to the diagonal length. The projected length is 265.656 centimeters and the width is 149.432 centimeters if you calculate according to the ratio of 16:9, and the projected length is 243.84 centimeters and the width is 182.88 centimeters if you calculate according to the ratio of 4:3.

Calculation procedure:

16:9 projection

Set the length to be 16a and the width to be 9a, from the collinear theorem we get

(16a)? + (9a)? = 120?

So a = 6.53682

So the length is 104.5891 inches, and the width is 58.8314 inches

Because 1 inch = 2.54 centimeters

So when converted to centimeters, the length is 104.5891 x 2.54 = 265.656; and the width is 58.8314?x 2.54 = 149.432 centimeters.

Similarly you can calculate that the length of a 4:3 scale projection is 243.84 centimeters and the width is 182.88 centimeters.

Expanded information:

There are two types of displays such as screen projections, one with an aspect ratio = 4:3 and the other with aspect ratio = 16:9

1 foot = 12 inches = 12 x 2.54 = 30.48 cm.

The inch (英寸) is a unit of length used in the United Kingdom (UK, i.e., Great Britain (Commonwealth) and its former colonies, generally 1in = 2.54cm, and in the British system, 12 inches is 1 foot and 36 inches is 1 yard.

In LCD monitors, the specifications are generally 17 inches, 19 inches, 22 inches and so on. In cell phones, screen sizes are now generally 4.0 inches, 4.2 inches, 4.5 inches, 4.7 inches, 4.8 inches, 5.0 inches, 5.2 inches, 5.5 inches, 5.7 inches, 6.44 inches and so on. In tablets, the screen sizes are usually 7.9″, 9.7″, and 12.9″. The size of the display is usually measured by the length of the diagonal in inches.

Baidu Encyclopedia - Inches