Answer: 6 units.
- A 4 units
- B 6 units
- C 8 units
- D 2 units
Correct answer: B. 6 units
Explanation: By the defining property of a parabola, the distance from any point on it to the focus equals its distance to the directrix. So the distance to the directrix is also 6 units.
All four conics form a single family distinguished only by eccentricity: a circle is the most "closed" (e=0), an ellipse is an elongated closed curve, a parabola is the borderline open curve (e=1), and a hyperbola has two separate open branches (e>1).
Concept context
Study circles, parabolas, ellipses, and hyperbolas as curves formed by intersecting a plane with a double cone, with their standard equations and key properties.