Extracted text: Point A has an elevation of 130.48 m above mean sea level while elevations at points B and C are unknown. An instrument was set at B whose height is 1.22 m above B. In that set-up, vertical angles are observed: to point A being -14°45' and to point C being +8°32'. If the horizontal distances AB and BC are 547.20 m and 923.95 m, respectively, determine the following: a.) Difference in elevation between A and B b.) Difference in elevation between B and C c.) Elevations of points B and C