the remaining angle for thw triangle is found by subtracting the already shown angles from 180 (the angle some of a triangle) which happens to be 96 to get 84 but now you need to subtract 84 from 180 to find the angle on the other side of line because lines have a total angle measurement of 180 but we already kbow what this get's us because it's 96 now we devide 96 by 6 to get 16 our answer.
