Answer:
60.65
Explanation:
The Law of Cosines can help you figure this out. Call the given sides "a" and "b" and the given angle "C". Then the third side, "c" will satisfy the relation ...
c² = a² + b² -2ab·cos(C)
= 33² +37² -2·33·37·cos(120°) = 3679
c = √3679 ≈ 60.65476 ≈ 60.65
The length of the third side is about 60.65 units.