Question 329518
When the ship goes 18 degrees and then turns to a bearing of S72E, it turns 90 degrees. 72+18=90.

Another way to look at it, S72E is equal to an azimuth of 108 degrees and a bearing of N18E is equal to an azimuth of 18 degrees. 108-18=90. 

So, we have a right triangle to deal with.

By Pythagoras, the distance back to the origin is {{{sqrt(82^2+46^2)=2*sqrt(2210)=94.02}}} miles.

We can find the bearing from the origin to the ship by 

{{{18+arctan(46/82)=47.29}}} degrees.

A bearing of N47.3E