Question

probe that pop angle of isoscalen triangle is supplementary​

Answer 1

Proof that the sum of the angles in a triangle is 180 degrees. If ABC is a triangle then <)ABC + <)BCA + <)CAB = 180 degrees. Draw line a through points A and B. Draw line b through point C and parallel to line a. Since lines a and b are parallel, <)BAC = <)B'CA and <)ABC = <)BCA'.