inwosu wrote:

A computer manufacturer claims that a perfectly square computer monitor has a diagonal size of 20 inches. However, part of the monitor is made up of a plastic frame surrounding the actual screen. The area of the screen is three times the size of that of the surrounding frame. What is the diagonal of the screen?

I get sqrt of 300 as well.

Let Sc = area of screen computer, Sf= screen frame , St= total screen.

*The diagonal St is 20 inches.

*As we know that it is a square, the diagonal divides it in 2 perfect rectangle triangles: 45 - 45 - 90------> 20/2^(1/2) - 20/2^(1/2) - 20.

*20/2^(1/2) is the measure side of the total screen St and from that the total area (square) is 20/2^(1/2) * 20/2^(1/2)= 200 inches^2.

* St = Sc + Sf and Sc = 3 Sp

3 Sp + Sp = 200 ----->> Sp = 5o inches^2 and Sc= 150 inches^2.

* The ares Sc= 150 and the screen is square.

one side of the screen = 150^(1/2) and using Pythagore the diagonale is { [150^(1/2)]^2 + [150^(1/2)]^2 }^ 1/2 =

300 ^ (1/2)