May someone help me with my "Cross Sections" review? I understood how to do other ones but these two questions have me stuck because I haven't seen any like them before. (Answers must be rounded to 3 decimal places)

Find the volume of the solid whose base is bounded by the graphs of f (x) - x2 and g (x) - 2 -x2 if the cross sections perpendicular to the x-axis are a) Circles whose diameters are parallel to the y-axis. b) Isosceles right triangles with one leg parallel to the y-axis and the other leg perpendicular to the xy plane