The ** Parabola** tool allows you to create either an

*open*or

*closed*parabola in a few different ways. In an

*open*parabola, the end points of the parabola are joined and the interior of the parabola is filled. For a

*closed*parabola, the endpoints of the parabola are not connected and the interior is not filled. The second Option Button offers these construction methods:

- Vertical open
- Vertical closed
- Horizontal open
- Horizontal closed

The first option button determines the way the important points of the parabola are defined. The options are

- Vertex first and then drag to define the arc endpoints
- Arc endpoint first and then drag to define the vertex and second arc endpoint
- Define the distance between the arc endpoints on the side of the parabola
the vertex and then drag to define the vertex*away from* - Define the distance between the arc endpoints on the side of the parabola
the vertex and then drag to define the arc endpoints*containing*

The last two options request the use of the mark button