Since you said angle, I assume you mean a triangle, so:
Take the number of the angles you have and add them, then, subtract it by 180. It gives you the missing angle of your triangle!
Answer:
2/3
Step-by-step explanation:
its the only possible answer looking at the chart since it's the only answer above zero and below one
Well 31 is not able to go any were and it has to stay 31