Sum of all angles in a triangle is 180°
90 + x + 50 + x + 60 = 180 | All angles add up to 180
200 + 2x = 180 | Combine like terms
2x = - 20 | Subtract 200
x= - 10 | Divide by 2
Find Angle A:
Angle A = x + 50
Angle A = -10 + 50
Angle A = 40
Answer: Angle A = 40