What is the axle thickness of the Kent Road Tech 700c bike? I need to know in order to find proper fitting anti theft nuts to keep the wheels from being stolen.
I can't find "roadtech" on www.kent.bike so there's no real way to look it up in the catalog.  I could only find some pictures on mass-market websites, and from the look of it, you've already got regular solid axles with hex nuts.

If I had to guess, I'd say 9mm on the front and 10mm on the rear, but that's totally a guess.

Your best bet is to measure.  Take one front nut and one rear nut to a hardware store and see what size bolt fits.  9mm and 10mm are the most likely, but 12mm and 3/8" are also possible.

The other thing you could do is just lock the wheels to the bike and park in a public place.  Those locking nuts are really expensive.