91 is identified on one angle, we can use the vertical theorem to identify the angle across it which is also 91, thus adding 2 sides up to 182 already.
The third side on the left is 89 because 360-182 is 178 and 178/2 is 89.
The final side is 89 but since there is an additional one W would have to be 88, thus the final answer is
W=88
