Solve for the unknown interest rate in each of the following: $($Do not round intermediate calculations and round your final $2$ decimal places.$)$

$\backslash$table$[[$Pre:$,$nt value,Years,Interest,Rate,Future Value$],[$$$,270,4,,x,336],[390,18,,$x$,1,230],[,,300,19,,\%,185,682],[,561,25,,\%,534,618]]$