Answer
A = $50^{\circ}$
Work Step by Step
in triangle ABC-
Given data is-
B = $30^{\circ}$
C = α + β = $100^{\circ}$
As we know that all the three angles of a triangle add up to 180 degrees, therefore-
A + B + C = $180^{\circ}$
A = $180^{\circ}$ - $(B+C)^{\circ}$
A = $180^{\circ}$ - $(30+100)^{\circ}$
A = $180^{\circ}$ - $130^{\circ}$
A = $50^{\circ}$
