Answer: 12.
- A 3
- B 6
- C 12
- D 24
Correct answer: C. 12
Explanation: For y² = 4ax the latus rectum is 4a; here 4a = 12.
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.