I spent a couple of minutes yesterday to perform simple geometric calculations processing some data obtained by me and my friends about 17 years ago (when we were 17).

We got all angular diameters and distances and we were able to evaluate linear distance between us and this. We were just too lazy to apply math skills acquired in school.

So,

Size = 40 m
Speed = 70 m/s = 260 km/h

Error is about 50%, of course.

Pretty natural, huh?