Respuesta :

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