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Trigonometry Problem?

A wall extending east and west is 6 feet high. The sun has an altitude of 49 degrees 31’ and is 47 degrees 20’ east of south. Find the width of the shadow of the wall on level ground.

1 Answer

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  • 9 years ago
    Favorite Answer

    Consider wall as a pole of 6 feet high, If sun makes an angle of 49 degree 31' or 49 31/60 = 49.516°its shadow on the ground will be

    |\

    |...\

    h|.....\

    |.......\

    |_____\

    <--L---->

    tan 49.516 = h / L

    or L = (h = 6) / 1.1715 ; tan 49.516 = 1.1715

    shadow (L) = 5.1215 feet

    Now the sun is shifted towards east of south by 47° 20' or 47.3333° so shadow on the ground will be

    shorter than this calculated as above

    .... *|\

    ....*. |...\

    ...*...|.....\ 5.1215

    .*.....|.......\

    *......|_____\

    <-----L------>

    ......<--w--->

    So now shadow of wall will be w feet wide instead of L feet, which can be calculated as

    cos 47.333 = w / 5.1215

    or w = 0.6773*5.1215 = 3.47 feet ----- Answer

    ----------------------

    It's bit difficult to explain without proper figure's in 3 D trigonometry, but I hope it would help you.

    Vick

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