Given the diagram below where O is the center of the circle

Given the diagram below, where O is the center of the circle, m

Solution

Answer to the question :

BCE + BCA = 180, because they lie on the same lines.

BCE = 180-80 = 100

In any quadrangle with circumscribed by circle, opposite angles sum to 180, we have BDE = 180-100 = 80
So, angle A = 180-80-50 = 50

Angle A = 50