QA-PUT-1: If I’m straddle putting, does my other foot have to be on a line perpendicular to my lie?
No. Your other foot can be as close to the target as the back of your marker. So, your other foot does not have to be directly to the side of the foot behind the marker. In fact, the foot behind your marker can be as much as 30cm back (the length of the lie) and/or 10cm to the side (half of the lie’s 20cm width), which means that your other foot can actually be closer to the target. It just can’t be closer than the back of your marker. Also remember that the shape that marks the same distance to the target as the back of your marker is a circle whose center is the target.