The hole in a ruler
This is an easy one. It’s for hanging it up. I’ll cover why the f#@! you’d want to hang up a ruler in the first place in my next article (I honestly won’t, I can’t think of a single reason. Just put it in a desk drawer like normal people).
The hole at the end of a tape measure
In today’s episode of “something I haven’t even seen an actual professional do with tools”, we discuss the tape measure hole. Apparently that’s where you hook it into a nail or screw so you can measure the distance without the risk of it slipping. Most tape measures also have that weird plastic lock thing you can use for the exact same thing, but at least you can do this. I guess.