Answer: 3/5.
- A 3/5
- B 4/5
- C 3/4
- D 5/3
Correct answer: A. 3/5
Explanation: e = √(1 − 16/25) = √(9/25) = 3/5.
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.