Recall the locus definition of a parabola (illustrated here if you need a refresher). Well, imagine spinning this parabola 360 degrees about its axis (of symmetry). Doing so yields a 3D solid called a circular paraboloid of revolution. Interact with this applet for a few minutes. Be sure to slide the Slide Me! slider completely once before messing around with the other sliders! Note: Point P is a point that lies on this surface. Move it wherever you'd like by using the xcoord and ycoord sliders. After doing so, answer the question that follows. To explore this resource in Augmented Reality, see the directions that appear below the applet.

1) Open up GeoGebra 3D app on your device. 2) Go to MENU, OPEN. Under SEARCH, type p2bnpakc. 3) The xcoord slider controls the x-coordinate of point P. The ycoord slider controls the y-coordinate of point P.The The yellow slider Filling controls the opacity of the paraboloid. The blue PlaneFilling slider controls the opacity of the (directrix) plane. The a slider stretches (or compresses) the paraboloid vertically (with respect to z). The slider named Animate provides the animation. Set the boolean variable ShowCrossSection equal to "true" if you want to see the 2d-parabola = cross section of the paraboloid of revolution and vertical plane containing P.