Lesson Plan


This article describes the concept of eccentricity of the conic sections as a unifying idea.


  • Mathematics > General
  • Mathematics > Algebra
  • Mathematics > Equations
  • Mathematics > Patterns
  • Science > General
  • Science > Astronomy

Education Levels:

  • Grade 9
  • Grade 10
  • Grade 11
  • Grade 12


Eccentricity Ellipse Circle Parabola Hyperbola student-facing



Access Privileges:

Public - Available to anyone

License Deed:

Creative Commons Attribution 3.0


Update Standards?

CCSS.Math.Content.HSG-GPE.A.2: Common Core State Standards for Mathematics

Derive the equation of a parabola given a focus and directrix.
Curriki Rating
On a scale of 0 to 3
On a scale of 0 to 3

This resource was reviewed using the Curriki Review rubric and received an overall Curriki Review System rating of 3, as of 2010-03-31.

Component Ratings:

Technical Completeness: 3
Content Accuracy: 3
Appropriate Pedagogy: 3

Reviewer Comments:

This lesson consists of a study of all conic sections viewed through the concept of eccentricity. By dividing the eccentricity e into cases, the author derives equations for all the familiar sections. The algebra is daunting but do-able. The major drawback of this approach, as opposed to the more familiar method of taking sections of a cone, is that the circle appears only as a degenerate point. The author has to argue from the point to the ordinary circle via limits.. This lesson is suitable for high school students who have mastered Algebra II and Pre-Calculus.
Chandra Parmar
October 14, 2009
A very good work in an evergreen subject like astronomy and geometry. Equations are useful to complete calculations about geometrical items to unfold interesting information. I am eagerly interested to…

Non-profit Tax ID # 203478467