Math Is Fun Forum

Au101

Member

Registered: 2010-12-01

Posts: 353

Bearings

God it's been a while, but I can do the trig, I just don't seem to be able to draw this diagram correctly. I've had a number of gos, where I've thought I've had it and yet, I always end up a long way out - an order of magnitude usually.

53. From A, the bearing of X, the foot of a tower, is 041° (N 41° E) and the angle of elevation of Y, the top of the tower, is 5°. The distance AX is 1000 m. From a point B, due E of A, the bearing of X is 313° (N 47° W). A, B and X lie in the same horizontal plane. Calculate
(a)  the height of the tower,
(b)  the distance BX,
(c)  the angle of elevation of Y from B.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,627

Re: Bearings

hi Au101

3D diagrams can get confusing, but, there's no reason why you shouldn't split this into a plan view and individual views for each point with the height of the tower.

The height can be found by h = 1000.tan(5) and, once you have BX, a similar one will enable you to get the angle of elevation from B

To get BX, use the sine rule:

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

Au101

Member

Registered: 2010-12-01

Posts: 353

Re: Bearings

Lovely stuff, such a great help