What should the approximate bond angles be for a molecule with a see-saw molecular geometry

To find the mass defect for uranium-238 several calculations must be made. which is the calculation that should be made first? assume atomic number for uranium-238 is 92. a. 92(1.0073) x 92(1.0087) = b. 92(1.0073) x 146(1.0087) = c. 146(1.0073) x 238(1.0087) = d. 238(1.0073) x 238(1.0087) =