A conveyor is used to lift paper to a shredder. The most efficient operating angle of elevation for the conveyor is 35.4°. The paper is to be elevated 13.0 m. What length of conveyor is needed?

I did

sin 35.4 =13/x
x=13/sin35.4
x= 22.44160629

I got two questions:
1) is this answer correct?
2) the question is asking for significant figures. how can I do it?