Originally Posted by
TankerDriver
I was never a trig fan, so I use the 60 to 1 rule, where at 60 DME, each radial is 1 mile apart. So at 15 DME, there are 4 radials per mile. If you're going from 360 to 180 on the 15 DME arc, it'd be 180/4 = 45 NM. I'm not quite sure I understand your equation above because I'm getting 15 NM for a 60 degree change on a 15 DME arc.
Tanker wins! I just did the 1:60 rule but with lots of guesstimating since it was like a 13DME arc along 70 degrees of arc or so. I guess I got it in the ballpark cause the guy asked me how i figured it out and I explained my method but told him im sure my math was off and he just said "OK, I was just seeing if you had a method".
The other method sounds good if you got a piece of scratch paper and a calculator but i think this guy just wanted to see if you could do some basic mental math.