Question

prove that the sum of a triangle is 180 if a+ b=120 and b+ c= 50 find angle b

Answer 1

a+b=120
b+c=50
b=25
then the sum of angles= 180

Answer 2

we know that π rad=180°
line parallel to any base and passes through opposite vertex⇔180° with one common angle and remaining two angle equal by alrenate opposite angles
Hence,sum of angle of triangle is 180°

a+b+c=180° only.