Question

Determine the prime factorization of 90.


A.


2 • 32• 5


B.


22• 11


C.


22• 3 • 5


D.


23• 11

Answer 1

my suggestion is a factor tree.

Answer 2

do you know how to do it?

Answer 3

no

Answer 4

okay. you have to find the factors of 90. then find the factors of the factors of 90 (but they must be composite). sounds complicated? but i will show you how to do it.

Answer 5

what are two factors of 90 that come up to your head?

Answer 6

now it's not that complicated though. since we know that 90 is an even number, it can be divisible by 2. but 2 times x will equal to 90. but what is x? (or what is the other product)?

Answer 7

You lost me like a Mile ago

Answer 8

okay. what are two factors (meaning what are two numbers) that can be multiplied together to get 90?

Answer 9

10*9

Answer 10

cool.

now find the factors of 10 and 9 each (since they both are composite numbers)?

Answer 11

what

Answer 12

first what are two numbers (when multiplied together) equal to 10?

Answer 13

2*5

Answer 14

good. now what are two numbers when multiplied together equal to 9?

Answer 15

3*3

Answer 16

now as you can see that i circled these last four numbers. these numbers are prime numbers and we can't break them down in the factor tree. they have factors of only one and itself. those are really the prime factorization.