Hey there, Nest!
A little tip that I think you'll find used is utilizing key words. In this, you can use the word "of" which usually signifies multiplication.
Therefore, if we have 3/4 of an hour, we multiply 3/4 by 60 seconds to get 180/4, which is actually 45 seconds.
To check this, we can divide 60 seconds into 4 segments of 15, and multiply that 1/4 by 3 to get 45 as 3/4.
I hope this helped you!