How much interest will Rich accrue during the 4.5-year nonpayment period?

Rich is attending a 4-year college. As a freshman, he was approved for a 10-year, federal unsubsidized student loan in the amount of $7,900 at 4.29%. He knows he has the option of beginning repayment of the loan in 4.5 years. He also knows that during this nonpayment time, interest will accrue at 4.29%.