Thanks Tycho, I wouldn't have figured that out by myself, I would have just wasted time picking up a calculator, when all I really need is one click to slide out your slide rule, and one sliding movement to match my speed with 90 degrees. Then I just look what the result is.
Doing this with a calculator would have required me to push a calculator button 10 times AND getting my eyes off the game. The slide rule way is 5 times less the work and unhindered concentration on the game