Did you know that Google Maps has a super-handy measuring tool? You have to enable it by clicking on the lab beaker icon, then click to enable "Distance Measuring Tool". Using this amazing little thing, I found that a walk around our yard, avoiding the poison ivy behind the shed in the top left of the picture, will take you almost exactly one-tenth of a mile. Our oldest son has to walk a mile as a prerequisite for a Boy Scout merit badge, so he's out there now walking around our yard 10 times.
Update: I was wrong about the merit badge. His pediatrician recommended more exercise & this is what the boy chose to do.