The diameters of the main rotor and tail rotor of a single-engine helicopter are 7.70 m and 0.99 m, respectively. The respective rotational speeds are 454 rev/min and 4,147 rev/min. Calculate the speeds of the tips of both rotors.

main rotor =180.6625215m/s

tail rotor ______m/s

Compare these speeds with the speed of sound, 343 m/s.
vmain rotor / vsound = .5267128908

vtail rotor / vsound = ______
I found the main rotor, but when i did the tail rotor i keep getting the wrong answer. I said it was 221.4791405m/s and that was wrong. sig figs don't matter in this assignment.