Question

Prove that the sum of the angles of a triangle is 180. In the figure. PQ || ST. Find x and y​

Answer 1

by alternate angle angle 60°= x

so x= 60°

and y+130°= 180. (linear pair)

so, y=180-130

y= 50°

And, x + angle A= 130° (sum of int. angle = exterior angle)

so x+ angle A =130°

60°+A=130°

A=130°-60°

A=70°

Now sum of angles.

A+ x+y

60°+50°+70= 180°

Hence, sum of all angles of triangle= 180°

proved