trigonometry

Asked by  | 11th Mar, 2009, 08:09: PM

Expert Answer:

         

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

      BC is the wall, at  C there is a window, CD is the pole pointing upwards

      To find length CD.

      Solution:

      1) In triangle ABC tan 300 =BC/AB

       

                                 1/  3=10/AB

                                   AB =103m

      2) In triangle ABC

      (AB)2  +(BC)2 =(AC)2

      (103)2 +(10)2 =(AC)2

      400=(AC)2

      20 =AC

       

      3) In triangle ACD  tan30o =CD/AC

                                      1/3 =CD/20

                                       CD =20/3

                                      CD =11.5m

    Therefore the rod is 11.5m long

           

 

 

 

 

Answered by  | 6th Jul, 2009, 11:35: AM

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