a string that is fixed at both ends has a length of $2\mathrm{.}39$ m$.$ When the string vibrates at a frequency of $79\mathrm{.}7$ Hz$,$ a standing wave with five loops is formed. $($a$)$ what is the wavelength of the waves that travel on the string? $($b$)$ what is the speed of the waves? $($c$)$ what is the fundamental frequency of the string?