Hello!
In order to find out the volume of any prism, you are to do length x width x height.
Because we only know the length and the width, we can multiply those to get started. 3 x 5 is 15, so we know that's what we can start with.
Because we know the volume, all we have to do is do h x 15 = volume (45). Now, what is height?
In order to find the height, we must find a number that, when multiplied by 15, equals 45.
So we can try out 3, which when multiplied by 15, equals 45.
That means 3 is your height.
Hope I helped! :)
