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

1 Answer
Oct 16, 2015

Answer:

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#.