Question

In a triangle ABC if angle A + angle C =140 and angle A+ 3 angle B=180then angle A is equal to

Answer 1

(angleA+angleC)+angleB=180 degree
140 degree+angleB=180 degree
angleB=180 degree - 140 degree
angle B=40 degree

angleA+3×angleB=180 degree
angleA+120 degree= 180 degree
angleA=180 degree-120 degree
angleA=60 degree