Assertion: parabola's directrix | /r/HasProperty | given
Facets:
Source sentences:
text: If the directrix and focus are given, a parabola can be constructed using the focal property, as shown at the right.
text: It is also possible to describe all conic sections in terms of a single focus and a single directrix, which is a given line not containing the focus.
text: Well, now we have an equation that will always find the equation of a parabola when only the directrix and focus are given.