Rhiannon Corporation has bonds on the market with 21.5 years to maturity, a YTM of 6.80 percent, and a current price of $1,045. The bonds make semiannual payments.

What must the coupon rate be on these bonds? (Do not round intermediate calculations and round your final answer to 2 decimal places. (e.g., 32.16))

I need to understand how the answer was found.