How to solve this manually ?
EDIT: In my module the answer is given as $0$ but when I used mathematica N[Sin[10 Degree] + Sin[20 Degree] + Sin[30 Degree] - Sin[360 Degree],50]
gives $1.0156683209925990818958162414 \cdots$ (truncated)
So I guess there is some mistake in the problem statement.