Answer
B = $20^{\circ}$
Work Step by Step
in triangle ABC-
Given data is-
A = $80^{\circ}$
C = α + β = $80^{\circ}$
As we know that all the three angles of a triangle add up to 180 degrees, therefore-
A + B + C = $180^{\circ}$
B = $180^{\circ}$ - $(C+A)^{\circ}$
B = $180^{\circ}$ - $(80+80)^{\circ}$
B = $180^{\circ}$ - $160^{\circ}$
B = $20^{\circ}$
