Menkaure's Pyramid was named 'Menkaure is Divine'. Smaller than his predecessors' pyramids at Giza, it has a base area of 102.2 x 104.6m (335 x 343 ft). - Lehner, Dr Mark, 'The Complete Pyramids', p.134 ...
The problem is Scott your dimensions used above yield an angle of 44.3351 degrees not 48 and 42. Again the angles you are using are arbitrary and are just being used by you to match the result not used to get the results.