How to prove that the sum of angles of a triangle is 180 degree.

1.	How to prove that the sum of angles of a triangle is 180 degree.
Answer» Let the triangle\'s of angle is x, y and zwe have to provex + y + z = 180 ..........(i)we know that sum of two interior opposite angle is equal to exterior angle.so, x + y = 180 - z ....... (ii)By linear pair exterior angle is 180 - z when triangle\'s angle is z.By (i) also we getx + y = 180 - z ..........(iii)Hence proved(ii) and (iii) are the same, so we can say that the sum of the three angles triangle is 180o.

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