How did Galileo determine the relative heights of the lunar mountains?

Answer

By observing how the shadows shortened as the sun rose higher over the feature

By analyzing how the length of the shadows changed relative to the angle of illumination, Galileo could deduce a corresponding height based on terrestrial analogues.

How did Galileo determine the relative heights of the lunar mountains?
GalileoastronomytelescopeobservationMoon