Using a builder’s level, the grade for a footing is being set. The bottom of the footing will be at elevation 94.00′. A backsight to the bench mark elevation 100.00′ has a rod reading of 4.70 . What should the rod reading be for the bottom of the footing if the grade is correct?

Using a builder’s level, the grade for a footing is being set. The bottom of the footing will be at elevation 94.00′. A backsight to the bench mark elevation 100.00′ has a rod reading of 4.70 . What should the rod reading be for the bottom of the footing if the grade is correct?