Answer
$3\times3\times3$
Work Step by Step
The first step is to write 27 at the top of your factor tree. The next question is what 2 numbers multiply together to get 27. For this example, I used 3 and 9. So, 3 and 9 are written under the 27 as 2 different "branches."
For each new number "branching" out from the previous number, you must determine if it is prime. 3 is prime because nothing multiplies to 3 but itself. Circle the number 3 to show its separation from the rest of the factor tree. 9, however, is not prime because 3 and 3 are another set of factors for 9 besides 9 itself.
Now, 3 and 3 are both prime, so circle each number separately.
Looking at all 3 circled numbers,$3\times3\times3$ would be the prime factorization for 27.
