# Direction of Segment. Reza Problem 3-20.

### #1 passpepasspe

passpepasspe

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Posted 16 October 2011 - 06:20 PM

Guys I am doing reza problem no. 20 in chapter 3 of his spring 2011 book.. Basically the problem asks for direction and length of segment BC.

No problem with the length.. however in the direction of segment BC, I am not sure how he got North East..Isn't he doing the direction CB in his solution?

The way I did the problem, I get SW. and I am not sure if i am doing correctly.

I took coordinates B and subtracted coordinates of C from B, i get negative values for both departures and latitude, so to me that is SW...

Looking at the coordinates you can tell that it is going NE though but not by the logic of positive negative for departure latitude.. which is really how all the proceeding problems have been done...

any help is appreciated... thanks..

### #2 eefeezy

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Posted 24 October 2011 - 11:53 PM

When you calculate Point B you should get approximately (x,y) ---> (23174, 22934). This is a great example to NOT trust the picture of the problem. If you were to plot points B and C, B to C is actually heading to the NE direction (positive departure and positive latitude). Use inverse tan(delta x/delta y) to obtain an 89 degree bearing.

Hope this helps!

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