So 2.5 os to 50, aka 2.5:50
divide each side by 2.5 to get the answer.
if you dont have a calculator, divide each side by 5 to get .5:10, multiply by 2 to get 1:20

a parallel line to that one above, will have the same exact slope, since parallel lines have the same slope.
It would go to the opposite side
780,120?
Attention:check before using this answer it may not be right.
Thank you.