The perimeter of a square-shaped piece of paper is 20 cm shorter than the height of a computer screen. How many cm is the height of the screen if the side of the square paper is 20 cm?
The perimeter of a square is found by 4*side, which means the square paper has a perimeter of 4*20 = <<4*20=80>>80
Since the perimeter of the square is 20 cm shorter than the height of the computer screen, the height of the computer screen is 20+80 = <<20+80=100>>100cm.
#### 100