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Problem with two review problems

  1. Dec 13, 2004 #1
    First of all, thanks for anyone who helps me with this

    1. Find the perimeter of an Isoceles triangle that has base angles of 36 degrees and an area of 580cm sq.
    The given answer is 126.4cm.

    2. A designer plan the top of a rectangular workbench to be four times as long as it is wide, and then determines that if the width is 2.5 ft greater and the length is 4.7ft less, it wouldbe a square. What are its dimensions?
  2. jcsd
  3. Dec 13, 2004 #2


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    1.& 2.What have you done so far???The problems are not difficult,and therefore it's better that u did them yourself,maybe with some help from us.Post your work.

  4. Dec 13, 2004 #3
    I just need help starting both of them, thats all.
  5. Dec 13, 2004 #4
    Well - what's the formula in getting the area of the triangle??
    You should start off with that.
  6. Dec 13, 2004 #5
    well i know that its 1/2(b)(h) but i don't know what it means by 2 base angles of 36 degrees. Since it's isocoles, doesn't it have a right angle, therefore 36+36+90=162 which it should add up to 180
  7. Dec 13, 2004 #6


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    I doubt the original problem was formulated with a triangle on a saddle (negative total curvature),but in a plane,so those angles should add up to 180°.
    U'll find more useful this formula:
    [tex] S_{triangle}=\frac{1}{2}l_{1}l_{2} \sin \alpha [/tex]
    ,where [itex] \alpha [/itex] is the angle between those 2 sides l_1 and l_2.

  8. Dec 13, 2004 #7
    isosceles doesnt mean right angle it's just
    36+36+ 108 = 180
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