answer
59
explanation
the total degrees in a circle is 360
so going counterclockwise, arc WX + arc XY + arc WY = 360
86 + 156 + WY = 360
WY = 360 - 86 - 156
WY = 118
WY is equal to the center angle, and the inscribed angle WXY is half of the center angle
WXY = WY/2
WXY = 118/2
WXY = 59
