In the order you have it from least to greatest is 1 3 2
The outlier is a because it is the most different value compared to the rest.
The total would be 180 degrees because angles on a straight line would always add up to 180.
(3x+31)+(2x-6)=180
5x+25=180
-25 -25
5x=155
/5 /5
x=31