$\backslash$table$[[$Amount of annuity,Interest rate,Period $($years$)],[$$$21,000,9\%,9]]$

a$.$ Calculate the present value of the annuity assuming that it is

$(1)$ An ordinary annuity.

$(2)$ An annuity due.

b$.$ Compare your findings in parts a$(1)$ and a$(2).$ All else being identical, which type of annuity$-$ordinary or annuity due$-$is preferable? Explain why.

The present value of the ordinary annuity is $ $($Round to the nearest cent.$)$