What we know:
For every 4 miles Vanessa jogs, Cody jogs 3 miles = 4/3
What we need to find: if Vanessa jogs 1 mile how far does Cody jog = 1/x where x represents Cody's miles.
Set up a proportion:
4/3 = 1/x
(4)(x)=(3)(1) cross multiply
4x=3
4/4x=3/4 multiplicative inverse
x=3/4 mile
If Vanessa jogged 1 mile, then Cody jogged 3/4 of a mile.