For this question, all you have to do is solve the missing angle of the triangle ABD since it has two measurements already and the angle BCD is a reflection of the missing angle.
Since the total degrees of a triangle's angles should add up to 180°, let's add the given angles and then subtract that from 180.
83 + 34 = 117°
180 - 117 = 63°
So, the angle BCD is 63°.
Hope that helped!
