Question

Fast food. If four out of five doctors prefer fast food,
then at a convention of 445 doctors, how many prefer fast
food?
4/5=x/445
5x=1780
x=356
please check if completed right

Answer 1

That is correct.

Note that you can simply multiply 445 by 4/5 and get the same answer (if your teacher does not require the extensive work that you showed).