Question

solve it: in a triangle ABC. AB=BC, ANGLE B=x and angle A=2x-20 degee. find angle b(with solution)

Answer 1

In triangle ABC, AB = BC. Therefore, angle B = angle C = x.
 Also given , angle A = 2x - 20.
 By angle sum property of a triangle,
 we have angle A + angle B + angle C = 180 degrees
 so , 2x - 20 + x + x = 180
 => 4x = 180 + 20 
 => 4x = 200           
 =>  x = 50 degrees
  Therefore, angle B = 50 degrees. (angle A = 2(50) - 20 = 80 degrees and angle C = 50 degrees)