How long does one revolution take for a rotating cd

Question

I have the question "When a cd rotates at an angular speed of 10.5 rads^-1, how long does one revolution take ?"

Here is my attempt.

Is this correct ?

Answer 1

0.59839860068 would be the result of the division, but it needs to be rounded to the least numerical accuracy of measurement values. 2 and $\pi$ are not measurement values, but 10.5 is.

10.5 has 3 "Significant figures".

So your answer also has to have 3 significant figures. The leading 0. do not count, so 0.598 would be the correct answer.