Answer:
As shown in picture:
Original x = 360 - (59 + 108 + 81) = 112 deg
Upper bound of x (when all known elements are considered at lower bound)
U = 360 - (58 + 107 + 80) = 115 deg
Lower bound of x (when all known elements are considered at upper bound)
L = 360 - (60 + 109 + 82) = 109 deg
Hope this helps!
:)
