100 inches projection size?

We’ve often come across the parameter ‘100 inches projection size’ in the description/detail section, some may comprehend this ‘100 inches’ as the width or height of the projection screen. Well, this ‘100 inches’ is referring to the diagonal length. Let’s take a closer look at the exact height and width of the projection screen?

In a more practical sense, if we know the accurate centimeters of the width and height of the 100 inches projection size, it would be much easier to make the purchasing decision based on the room size and display effect requirements.

Before rambling on numbers and calculations, we first need to know the aspect ratio of the screen. There are two commonly used aspect ratio: 16:9 and 4:3.

The proportional relationship between the height and width of a rectangle is what is aptly referred to as an aspect ratio.

For 16:9 aspect ratio screen

Width = diagonal × 0.8716

Height = diagonal × 0.4903

100 inches screen size

Width = 100 × 0.8716 = 87.16 inches = 87.16 ×2.54 = 221.39 (cm)

Height= 100 × 0.4903 = 49.03 inches = 49.03 × 2.54 = 124.54 (cm)

For 4:3 aspect ratio screen

Width = diagonal × 0.8
Height = diagonal × 0.6
100 inches screen size
Width = 100 × 0.8 = 80 inches = 80 × 2.54 = 203.2 (cm)
Height = 100 × 0.6 = 60 inches = 60 × 2.54 = 152.4 (cm)

16:9 aspect ratio is more friendly for movies, widely applied in home theaters. 4:3 aspect ratio has been used in conference rooms or classrooms. It is essential to find the appropriate aspect ratio for the space where the projector and the screen will be installed. 
More directly, just search for aspect ratio calculator, there’s a good one from projectorscreen.com, also could help calculate view distance resolution.