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Math Help - bearings, triginometry

  1. #1
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    bearings, triginometry

    A helicopter flies on a bearing of 200 from A to B, where AB=70 km. It then flies on a bearing of 150 from B to C, where C is due south of A. Work out the distance of C from A.

    can someone please tell me what is wrong with the diagram I have drawn?
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  2. #2
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    The helicopter moves from A to B on a bearing of 200, so the point B should actually be on the other side of A as 200>180.You should end up with a triangle with C directly below A, where AB=70km. you then need to work out angles ABC and BCA so you can use the sine rule to find the length of AC.
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  3. #3
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    Hello, Tweety!

    A helicopter flies on a bearing of 200 from A to B, where AB = 70 km.
    It then flies on a bearing of 150 from B to C, where C is due south of A.

    Find the distance from C to A.
    The first leg of the flight looks like this:
    Code:
                :
                :
                :
              A *
               /  200
           70 / 
             /
            /
           /
        B *

    The second leg looks like this:
    Code:
          :
          :
        B * 150
          :\
          : \
          :  \
              \
               \
                * C

    So the diagram should look like this:
    Code:
          :           * A
          :         * |
          :   70  *20|
          :     *     |
          :20*       |
          : *         |
        B * 130      |
          : *         |
          :30*       |
          :     *     |
          :       *30|
          :         * |
          :           * C
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  4. #4
    A riddle wrapped in an enigma
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    Quote Originally Posted by Tweety View Post
    can someone please tell me what is wrong with the diagram I have drawn?
    Hi Tweety,

    See diagram. And see Soroban's post for the angles.
    Attached Thumbnails Attached Thumbnails bearings, triginometry-bearing.bmp  
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