When doing Trigonometry do you round the answer to three significant figures?

Answer 1

The answer is not as simple as that. You have to know the accuracy of the measurements or values that are supplied to use. Also, the accuracy requirements of the calculation matter.

Here is a choice:

If calculations were made to determine the pitch of a roof, then measurements and requirements might not dictate 3 place precision. While accuracy in carpentry is important, one or two digits are about the limit of most woodworking measurement tools.

However, if we were trying to calculate the launch trajectory of a space craft to its destination, we would use ten (10) or more significant figures and we would insist on similar accuracy in the measured distances and values used, if not better. Ten significant digits might not be accurate enough. That would depend on how far away the target is.

No one wants to miss Mars after traveling that far! Especially those who made the trip.