Question

A Sony television has a rectangular screen with a diagonal measurement of 18 inches If the screen has a height of 10 inches, what is the length of the screen? Round to the nearest whole number.

Answer 1

Let's draw a figure from the statements in the problem. It can look like this:

The diagonal is 18 inches, the height is 10 inches and the length is x inches.

We can use the pythagorean theorem [ c^2 = a^2 + b^2 ] to solve this problem easily.

Looking at the top triangle, we can write:

`18^2=10^2+x^2`

With the help of a little algebra, let's solve for x, the length. Shown below:

`\begin{gathered} 18^2=10^2+x^2 \\ 324=100+x^2 \\ x^2=324-100 \\ x^2=224 \\ x=\sqrt[]{224} \\ x\approx14.97 \end{gathered}`

Rounding to the nearest whole number, the length of the screen is:

15 inches