Question

prove than the sum of the interior angle of a triangle is two right angle​

Answer 1

Answer:

Yes it is

Explanation:

From External Angle of Triangle equals Sum of other Internal Angles: ∠ACD=∠ABC+∠BAC. ... But from Two Angles on Straight Line make Two Right Angles, ∠ACB+∠ACD equals two right angles. So by Euclid's First Common Notion, ∠ABC+∠BAC+∠ACB equals two right angles.