determine if the following ratios form a porportion.

If a/b=c/d is true, they are a proporion
if a/b=c/d, then ad=bc is also true

if 9/5=10/18 is true then
9*18=10*5 should be true
162=50
false

easier way
just simplify them
9/5 is simplified already
10/18=5/9

9/5=5/9
no

they do not