Respuesta :

∠TRS = 180° - 9x°

(180° - 9x°) + (9° + x) + 5x = 180°
180° - 9x° + 9° + x° + 5x = 180°
9° = 9x° - x - 5x
9° = 3x
x = 3°

The graph is really out of shape...