Results 1 to 4 of 4

Math Help - prove?

  1. #1
    Junior Member
    Joined
    Dec 2008
    Posts
    68

    Lightbulb prove?

    How to prove the sum of angles of traingle are 180
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member Mauritzvdworm's Avatar
    Joined
    Aug 2009
    From
    Pretoria
    Posts
    122
    in the picture C=A+B

    we know that the sum of all angles on straight line is 180, so the conclusion follows.
    Attached Thumbnails Attached Thumbnails prove?-triangle.jpeg  
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Banned
    Joined
    Oct 2009
    Posts
    4,261
    Thanks
    2
    Quote Originally Posted by Mauritzvdworm View Post
    in the picture C=A+B

    we know that the sum of all angles on straight line is 180, so the conclusion follows.

    Well, for this you ust first know that an exterior angle of atringel equals the sume of the two triangle's angles which aren't besides it, and this is usually done precisely using the fact that the sum of any triangle's angle's is 180 deg.

    Another way, perhaps more basic, to prove that is to choose any side of the angle and then through the opposite vertex to draw a line parallel to this side. Then, using the well known equalities between angles wrt parallel lines we get what we want.

    Tonio
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Member Mauritzvdworm's Avatar
    Joined
    Aug 2009
    From
    Pretoria
    Posts
    122
    oh, yes! I used a sledge hammer to crack open a wallnut...

    from the picture it is clear
    Attached Thumbnails Attached Thumbnails prove?-triangle2.jpeg  
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Prove
    Posted in the Calculus Forum
    Replies: 4
    Last Post: October 10th 2010, 12:28 PM
  2. Prove(10)
    Posted in the Trigonometry Forum
    Replies: 5
    Last Post: February 26th 2010, 05:16 AM
  3. Replies: 2
    Last Post: August 28th 2009, 03:59 AM
  4. How do I prove b^x * b^y = b ^ x + y on R?
    Posted in the Calculus Forum
    Replies: 2
    Last Post: October 25th 2008, 01:15 AM
  5. Prove:
    Posted in the Algebra Forum
    Replies: 1
    Last Post: October 25th 2008, 12:45 AM

Search Tags


/mathhelpforum @mathhelpforum