Finding Sample Standard Deviation

Given this information, how would you know the sample standard deviation?

1) Your company has a contract to provide 3,000,000 bolts to a Chinese manufacturer. The average length of the bolts must be 1 inch, with a standard deviation of no more than .05 inches. If their purchasing officer finds evidence, at the .05 level of significance, that these standards are not met, he will reject the entire shipment. After making 100 bolts, you carefully measure the lengths of 100 randomly chosen bolts. The mean length of the sample is 1.01.

I need the sample standard deviation to input into Excel to find the t-test statistic and am stuck on that part...thanks