pOn a piano, a key has a frequency, say f$0.$ Each higher key $($black or white$)$ has a frequency of f$0*$ rn$,$ where n is the distance $($number of keys$)$ from that key, and r is $2(1/12).$ Given an initial key frequency, output that frequency and the next $3$ higher key frequencies.

Output each floating$-$point value with two digits after the decimal point, then the units $("$Hz$"),$ then a newline, using the following statement:

print$($f$\text{'}\{$your$\_$value:$\mathrm{.}2$f$\}$ Hz$\text{'})$