Home›Lesson Plans›Mathematics›Analytic Geometry · Grade 12

Conic Sections: Slicing a Cone

Twelfth graders explore the four conic sections — circle, ellipse, parabola, and hyperbola — the elegant curves formed by slicing a cone, each with its own equation and real-world applications from orbits to headlights.

Grade 12Conics55 minutes1 class periodGradual ReleaseExplicit teaching4 StandardsCommon Core
Start the Lesson
Lesson at a Glance

Everything you need before the bell rings

Learning Objectives

Students will be able to…

  • ✓Identify the four conic sections.
  • ✓Recognize each equation.
  • ✓Connect conics to real applications.
  • ✓Distinguish the curves.
Essential Question

Slice a cone at different angles and you get a circle, an ellipse, a parabola, or a hyperbola. These four curves appear everywhere — in orbits, dishes, and bridges. What are they?

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Lesson Phases
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Vocabulary Terms
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Standards Aligned
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Interactive Task
Conics Explorer · Interactive

The Conics Explorer

Project this and tap each conic section. Have students learn how slicing a cone creates circles, ellipses, parabolas, and hyperbolas!

🔺 Explore the conic sections — tap eachTry it

The Lesson · Gradual Release (I Do · We Do · You Do)

55 minutes, five moves

Tap any phase to open the teacher moves and student actions.

1

Launch — Slicing a Cone

5 min

Slice a cone at different angles — what curves appear?

👩‍🏫 Teacher Moves

  • Show cone cross-sections.
  • Ask what curves form.
  • Set the goal: conic sections.

🎒 Student Actions

  • See the slices.
  • Wonder the curves.
  • Predict them.
2

I Do — Four Curves

10 min

Teacher models.

👩‍🏫 Teacher Moves

  • Circle and ellipse.
  • Parabola.
  • Hyperbola.

🎒 Student Actions

  • Learn circle/ellipse.
  • Learn parabola.
  • Learn hyperbola.
3

We Do — Explore Together

13 min

Class uses the Conics Explorer.

👩‍🏫 Teacher Moves

  • Tap each conic.
  • Note the equation.
  • Connect to applications.

🎒 Student Actions

  • Tap each.
  • Note equations.
  • Connect apps.
4

You Do — On Your Own

12 min

Students identify.

👩‍🏫 Teacher Moves

  • Identify conics from equations.
  • Match to applications.
  • Sketch each curve.

🎒 Student Actions

  • Identify them.
  • Match apps.
  • Sketch them.
5

Close — Close

5 min

One conic.

👩‍🏫 Teacher Moves

  • Give an equation.
  • Identify the conic.
  • Hand out the exit ticket.

🎒 Student Actions

  • Identify it.
  • Explain it.
  • Complete the exit ticket.
Standards Alignment

Built to the standards you report on

Aligned to the Common Core State Standards for Mathematics (High School · Precalculus).

CCSS
G-GPE.1

Derive the equation of a circle given center and radius.

CCSS
G-GPE.2

Derive the equation of a parabola given a focus and directrix.

CCSS
G-GPE.3

Derive the equations of ellipses and hyperbolas.

CCSS
A-REI.7

Solve systems involving a linear and a quadratic equation.

Differentiation

One lesson, every learner

Multilingual Learners

ELL / EMERGING READERS
  • Conic + equation + picture cards.
  • Sentence frame: “A ___ is formed by ___.”
  • Use physical cone models.

Support & Access

IEP / 504
  • Start with circle and parabola.
  • Match picture to name.
  • Use a cone model.

Stretch & Extend

GIFTED / EARLY FINISHERS
  • Graph a conic from its equation.
  • Find foci and vertices.
  • Explore eccentricity.
Materials

What to gather

  • 📽️Projector / board
  • 🔺Cone models
  • 💻The Conics Explorer
  • 📈Graph paper
  • ✏️Pencils
  • 🎫Exit-ticket slips
Vocabulary

Key terms — hover for a quick definition

conic sectiona curve from slicing a conecirclepoints equidistant from a centerellipsean oval with two fociparabolaa U-shaped quadratic curvehyperbolatwo opening-apart curvesfocusa special point defining a conicdirectrixa line defining a parabolavertexa turning point of a conic
Evaluate

Exit Ticket

Preview the three formative checks. Tap “Sample answer” to see what mastery looks like — hide them before you print for students.

QUESTION 1
What are the four conic sections?
Circle, ellipse, parabola, and hyperbola.
QUESTION 2
What is the equation of a circle with center (h, k) and radius r?
(x − h)² + (y − k)² = r².
QUESTION 3
What real-world path is an ellipse?
A planet’s orbit around the sun.

Going deeper? Foci and eccentricity.

Have students explore how the foci and eccentricity of an ellipse determine how “stretched” it is. A printable conics sheet is in the Math library.

Study · Flashcards

Study the key terms

Tap a card to flip it, then rate whether you knew it. Built from this lesson’s vocabulary.

🃏 Conic SectionsFlip
Card 1
Term
Tap to flip →
Meaning
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Practice · Quiz

Check your understanding

A quick self-check with instant feedback, drawn from this lesson’s key terms.

📝 Conic SectionsQuiz
Score: 0
1 / 6
Question 1
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Practice · Worksheet

Printable worksheet

A print-and-go review sheet with a built-in answer key. Tap “Show answer key” to reveal answers, or print the clean version for students.

🖨️ Conic SectionsPrint
Name: ________________________
Date: ____________

Part A · Write the word that matches each meaning

Word bank: circle, conic section, directrix, ellipse, focus, hyperbola, parabola, vertex
  1. a special point defining a conic
  2. two opening-apart curves
  3. a line defining a parabola
  4. a turning point of a conic
  5. a curve from slicing a cone
  6. an oval with two foci
  7. a U-shaped quadratic curve
  8. points equidistant from a center

Part B · Show what you learned

  1. What are the four conic sections?
  2. What is the equation of a circle with center (h, k) and radius r?
  3. What real-world path is an ellipse?
Answer key — Part A: 1) focus · 2) hyperbola · 3) directrix · 4) vertex · 5) conic section · 6) ellipse · 7) parabola · 8) circle
Part B: 1) Circle, ellipse, parabola, and hyperbola. 2) (x − h)² + (y − k)² = r². 3) A planet’s orbit around the sun.