Find the diagonal in a rectangle with a side of 9cm and an area of 108cm ^ 2.

Step one.

First, we need to determine what value the other size of this rectangle will be, because from the condition of our task we know for sure that with an area of 108 cm2, its first size is 9 centimeters:

108: 9 = 12.

Step two.

Now we can determine what the diagonal in this rectangle will equal, for which we should use the formula known from the school course from the Pythagorean theorem:

√ (9 ^ 2 + 12 ^ 2) = √ (81 + 144) = √225 = 15.

Answer: Diagonal = 15 cm.