Geometry Homework

Question

A computer monitor is 20 inches wide. The aspect ratio, which is the ratio of the width of the screen to the height of the screen is 16:9. What is the length of the diagonal of the screen, to the nearest whole inch ?

Answer 1

When you're working with a right triangle the sum of the squares of the two sides making up the right angle is equal to the square of the hypotenuse.

a^2 + b^2 = c^2

16^2 + 9^2 = c^2

256 + 81 = c^2

337 = c^2

Square root of 337 = c

c = 18 (rounded)