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Math Help - Is this possible?

  1. #1
    Member jacs's Avatar
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    Question Is this possible?

    Is it possible to prove a triangle ABC is isosceles, given only that Ậ = 50

    ???????


    thanks



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  2. #2
    Grand Panjandrum
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    Quote Originally Posted by jacs
    Is it possible to prove a triangle ABC is isosceles, given only that Ậ = 50

    ???????


    thanks



    No. Since an isosceles triangle must have two equal angles, but the only
    constraint on a general triangle is that the angle sum is 180 degrees.
    So a triangle with an angle of 50 degrees could have its other angles as
    60 and 70 degrees and hence need not be isosceles.

    RonL
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  3. #3
    Member jacs's Avatar
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    thanks for that, that is pretty much what i thought too, but teacher insists it can be done.

    Should get his working tomorrow, which will prove interesting. I guess he must know some alternate universe geometry that we don't.

    Or perhaps he just gave us the wrong info, (wouldnt be the first time)
    lol

    i will post his answer for a laugh, see what he manages to come up with

    thanks CaptainBlack
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  4. #4
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    how come the other two angles couldn't be 65 degrees?
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  5. #5
    Grand Panjandrum
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    Quote Originally Posted by c_323_h
    how come the other two angles couldn't be 65 degrees?
    They could be, but you can't prove that they must be (at least not
    without some additional conditions).

    RonL
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  6. #6
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    Quote Originally Posted by jacs
    thanks for that, that is pretty much what i thought too, but teacher insists it can be done.

    Should get his working tomorrow, which will prove interesting. I guess he must know some alternate universe geometry that we don't.

    Or perhaps he just gave us the wrong info, (wouldnt be the first time)
    lol

    i will post his answer for a laugh, see what he manages to come up with

    thanks CaptainBlack
    Perhaps your teacher thinks in Lobachevskian Space?
    (No idea how to spell it)
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  7. #7
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    Quote Originally Posted by ThePerfectHacker
    Perhaps your teacher thinks in Lobachevskian Space?
    (No idea how to spell it)
    Still not a theorem in hyperbolic or elliptic geometries

    RonL
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  8. #8
    Member jacs's Avatar
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    Well, it turns out, ooopps surprise, he forgot a vital peice of information, like the second angle is also 50.

    So that solves that little quandary, thanks for you input everyone.

    jacs
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