Answer:
Cody is 60 inches tall.
Explanation:
Let
be the initial height of Cody and Tyler, then we know that now Cody's height
is 20% more than
, or

and Tyler's height has increased half as much as the initial height; or

Now Tyler is 4 feet tall; therefore ,

is the initial height of Cody and Tyler.
Now Cody has grown as half as much as his initial height; therefore:


When converted to inches, this is 60 inches.
Therefore Cody is 60 inches tall.