Question

what is the sum of the all the angles of a triangle

Answer 1

Answer:

180 degrees

Step-by-step explanation:

Answer 2

Answer:

The sum of the angles in a triangle is 180 degree.

Step-by-step explanation:

Theorem :- If ABC is a triangle then <)ABC + <)BCA + <)CAB = 180 degrees.

Proof :-

Draw line a through points A and B. Draw line b through point C and parallel to line a.  (Then we will get a fig as shown)

Since lines a and b are parallel, <)BAC = <)B'CA and <)ABC = <)BCA'.

It is obvious that <)B'CA + <)ACB + <)BCA' = 180 degrees.

Thus <)ABC + <)BCA + <)CAB = 180 degrees.

Hope this helps you.. :)