Three discrete spectral lines occur at angles of 10.09, 13.71, and 14.77 in the first-order spectrum of

Question:

Three discrete spectral lines occur at angles of 10.09°, 13.71°, and 14.77° in the first-order spectrum of a grating spectrometer.
(a) If the grating has 3 660 slits/cm, what are the wavelengths of the light?
(b) At what angles are these lines found in the second-order spectrum?