Find Distance from Ship to Lighthouse

G

greatwhiteshark

Full Member
Joined
May 8, 2005
Messages
279
The navigation on a ship traveling due east at 8 mph sights a lighthouse at a bearing of S55(degrees)E. One hour later the light house is sighted at a bearing of S25(degrees)W. Find the closest distance the ship came to the lighthouse. (Round to two decimal places.)
 
Again, draw the picture. Figure out that one piece is 8 mi. Label what you know with what you know. Draw some right triangles. label what you don't know with variables. Figure it out.
 
Not really. Once you get a drawing, just look around for what you need. It isn't going to fall out of the sky. You have to look at it, draw it different ways, ponder it, and just try to find what makes sense. That's all I do. I do not care if I find the best way to solve it. I'm just trying to solve it.

Some definitions:
The ship starts at A and ends at B, 8 miles due East of A.

Somewhere between A and B, the ship has travelled a distance of X miles to point C, the closest it will get to the lighthouse.

The distance from C to the lighthouse is what we are looking for. Call it d.

We have:

tan(55º) = d/x
tan(25º) = d/(8-x)

Solve for d and x. Really, thought, 'x' is superfluous, but we may need it in a subsequent question.
 
You must log in or register to reply here.
Top