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Math Help - 3d problems

  1. #1
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    3d problems

    Can someone help me with this question?

    Standing due south of a tower 50 m high, the angle of elevation of the top is 26◦.What is the angle of elevation after walking a distance 120 m due east?

    The question has me confused so I can't draw a diagram.
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  2. #2
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    Ok this problem has to be done in a few parts. A diagram will really help here.

    Firstly find the horizontal length from the tower before moving eastward.

    You get \displaystyle \frac{50}{\tan 26^o} Do you know why?

    Now using pythagora's thm, find the horizontal distance from the tower with the 120m and the value you just found. What do you get?
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  3. #3
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    Hi pickslides.

    I understand the first part:



    So x will be the horizontal length you're talking about and C is the thing standing due south.

    mm.. After thinking about your post I drew this diagram:



    T is tower, x is the horizontal distance in the previous diagram and b will be the distance from the tower to the location after moving 120m due east.

    After that we can make b the base of a right-angled triangle and T the height, so it will look like this:



    Theta will be our answer

    So \displaystyle \frac{50}{\tan 26^o}

    x=102.515

    Then we can use pythag... b= \sqrt {102.515^2+ 120^2}

    b=157.827

    Now we know two sides of the last triangle...

     \tan\theta = \displaystyle\frac {50}{157.827}

     \theta = \tan^{-1} (\displaystyle\frac{50}{157.827})

     \theta = 17.58^o

    :S
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  4. #4
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    Sounds good to me!
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