Respuesta :

50°

Step-by-step explanation:

40° + 90° + ? = 180°

130° + ? = 180°

? = 180° - 130°

? = 50°

Answer: 50 degrees

Step-by-step explanation: The interior angles add up to 180.

1. 40 + 90 + ? = 180

     130 + ? = 180

   -130         - 130

            ? = 50