Question

The diagonal of a rectangle measures 13 centimeters. One side is 12 centimeters long. How do you find the length of the other side?

Answer 1

The lenght is `5` cm.

Explanation:

Let's say that the `12`-centimeters side is the horizontal one. So, we must find the lenght of the vertical one, which we call `x`.

Notice that the horizontal side, the vertical one and the diagonal form a right triangle, where the catheti are the sides of the rectangle and the hypotenuse is the diagonal. So, using Pythagora's theorem we get

`13^2 = 12^2+x^2`

From which we obtain

`x=sqrt(13^2-12^2)=sqrt(169-144)=sqrt(25)=5`.