Part A What are the three longest wavelengths for standing waves on a 273-cm-long string that is fixed at both ends? Enter your answers in meters in descending order separated by commas. 17 A, A2, A3 = Submit Request Answer Part B 3 = If the frequency of the second-longest wavelength is 51 Hz, what is the frequency of the third-longest wavelength? Express your answer with the appropriate units. A Value Units ? ? m