Opera singer and crystal goblet

[cctroublemaker]

Standing-wave vibrations are set up in a crys-
tal goblet with four nodes and four antinodes
equally spaced around the 10:6 cm circumfer-
ence of its rim.
If transverse waves move around the glass
at 900 m=s, an opera singer would have to
produce a high harmonic with what frequency
in order to shatter the glass with a resonant
vibration? Answer in units of kHz.

I'm stuck on this problem, please help.

 

[Kurdt]

If the rim has a wave with 4 nodes and 4 antinodes then what is the wavelength of that wave considering the rim is 10.6cm? Since you are given the wave speed do you know of any equation that relates the wave speed the wavelength and the frequency?