 First, notice that NW is four quarter-winds above W, so looking up on the "toleta", in the q = 4 row, the "alargar" is 71 miles for every 100 miles on the NW course.But the ship only sailed 40 miles overnight, so we have to solve the ratio 71/100 = "x"/40, which by the rule of three means "x" = alargar = 28.4 miles.In other words, by the overnight sailing NW by 40 miles from A to C, the ship is now 28.4 miles away from its "intended" Westward course.