Using focus-directrix graph paper, create a parabola that has a horizontal directrix that is four units above the focus. You can get focus-directrix paper on the Lesson 12.1.4 Resource Page available at cpm.org. Click in the lower right corner of the graph to view it in full-screen mode.
Use this eTool to create a Parabola
Click the link at right for the full version of the eTool: 12-96 HW eTool