National defense and 6th grade math

(Image from http://www.festungguernsey.supanet.com/about_us.htm) Imagine an observer with a stereoscopic rangefinder and a telephone, camouflaged on a seashore. The observer is 3km ahead of a cannon located further inland for concealment. The bearing is between the cannon and the observer is, for … Continue reading National defense and 6th grade math