For the following exercises, draw an outline of the solid and find the volume using the slicing method. 68. The base is a circle of radius a. The slices perpendicular to the base are squares. Q. The base is a triangle with vertices (0, 0) , (1, 0) , and (0, 1) . Slices perpendicular to the X-axis are semicircles. 70. The base is the region under the parabola y = 1 3c2 in the first quadrant. Slices perpendicular to the xy- plane and parallel to the yaxis are squares. 2 E. The base is the region under the parabola y = 1 x and above the x-axis. Slices perpendicular to the yaxis are squares. 72. The base is the region enclosed by y = x2 and y = 9. Slices perpendicular to the x-axis are right isosceles triangles. The intersection of one of these slices and the base is the leg of the triangle. E. The base is the area between y = x and y = x2. Slices perpendicular to the x-axis are semicircles