Question

What are the factors of 15? Use an area model to find the factors.

Answer 1

In order to find the factors of 15, let's write this number as a product of two number x and y, representing the area of a rectangle:

`15=x\cdot y`

Then, choosing natural values for x and calculating y, we have:

`\begin{gathered} x=1\colon y=(15)/(1)=15 \\ x=2\colon y=(15)/(2)=7.5 \\ x=3\colon y=(15)/(3)=5 \\ x=4\colon y=(15)/(4)=3.75 \\ x=5\colon y=(15)/(5)=3 \end{gathered}`

We can see that the only pair of numbers that are both natural (besides 1 and 15) are the numbers 3 and 5.

Therefore the factors of 15 are 3 and 5.