# Sum of Angles in a Triangle.

Can anyone please explain how to form a better idea in understanding Sum of measures of angles in a triangle are 180 degrees.

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

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.