Respuesta :

Answer:

Sorry I don´t know the answer but I tried

Step-by-step explanation:

sygify

Answer:

x° = 99°

Step-by-step explanation:

Sum of angles on a straight line is 180°.

  • 180° - 123° = 57° (sum of angles on a straight line)

Sum of angles in a triangle is 180°. Let u be the value of the unknown angle in the triangle.

  • 57° + 42° + u° = 180°

u° = 180° - 57° - 42°

u° = 81°

Sum of angles on a straight line is 180°.

  • x° + 81° = 180°

x° = 180° - 81°

x° = 99°