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?
Thoughts? Step-by-step reasoning:
The perimeter of a square is found by 4 * side, which means the square paper has a perimeter of 4 * 20 = 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 = 100cm.
Thus, the answer is 100.