2
$\begingroup$

Can anyone please explain how to form a better idea in understanding sum of measures of angles in a triangle is $180^\circ$ ?

$\endgroup$
  • 1
    $\begingroup$ Maybe this $\endgroup$ – David Mitra Jan 31 '12 at 21:41
  • $\begingroup$ if a ray stand on a line then the sum of the adjactent angels so formed is 180degree $\endgroup$ – user34792 Jun 30 '12 at 14:46
14
$\begingroup$

How about this?

Here, we use the linear pair axioms (version 1, below) and the fact that the alternate interior angles of are equal when a parallel line is intersected by a transveral.

Linear Pair Axioms:

  1. If a ray stands on line, then the sum of two adjacent angles so formed is $180^\circ$.
  2. If the sum of two adjacent angles is $180^\circ$, then the non-common arms of the angles form a line.

angsumtriangle

P.S.: I think these are more intuitive facts in geometry.

| cite | improve this answer | |
$\endgroup$
  • $\begingroup$ +1 Elementary result, of course, but a very nice explanation indeed $\endgroup$ – Dilip Sarwate Feb 2 '12 at 1:40

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.