$5\mathrm{.}16$: $($Solving for i$)$ Kirk Van Houten, who has been married for $23$ years, would like to buy his wife an expensive diamond ring with a platinum setting on their $30-$year wedding anniversary. Assume that the cost of the ring will be $$12,000$ in seven years. Kirk currently has $$4,510$ to invest. What annual rate of return must Kirk earn on his investment to accumulate enough money to pay for the ring?