Class 11 Maths NCERT Solutions Chapter 10 Conic Sections | Boundless Maths
Chapter 10 Class 11 Maths NCERT Solutions · Unit III · Coordinate Geometry

Class 11 Maths NCERT Solutions Chapter 10: Conic Sections

Free, step-by-step NCERT Solutions for all four exercises of this chapter — the circle, parabola, ellipse and hyperbola: their standard equations, foci, vertices, axes, eccentricity and latus rectum — plus the Miscellaneous Exercise where these curves turn up in reflectors, arches, bridges and racecourses. Solved the way CBSE awards marks, with the key formulas and the mistakes that cost students marks every year, right on this page.

Conic Sections gets its name from the fact that all four curves — circle, parabola, ellipse, hyperbola — are what you get when a plane slices through a double cone at different angles. Each curve is then defined purely in terms of distances (from a point, or from a point and a line, or from two points), which is what lets every one of them be pinned down by a single clean equation once its centre or vertex is placed at the origin.

5Exercises (incl. Misc.)
70Total Questions
2026-27CBSE Syllabus
100%Solved

Class 11 Maths NCERT Solutions Chapter 10 — Overview

This Class 11 Maths NCERT Solutions Chapter 10 hub covers Conic Sections — the circle, parabola, ellipse and hyperbola — each defined as a locus satisfying a distance condition. A circle is every point at a fixed distance (the radius) from a fixed centre. A parabola is every point equidistant from a fixed point (the focus) and a fixed line (the directrix). An ellipse is every point where the sum of distances to two fixed foci stays constant, and a hyperbola is every point where the difference of those two distances stays constant.

Once the vertex or centre of each curve is placed at the origin with its axis along a coordinate axis, these geometric definitions collapse into clean standard equations: (x-h)^2+(y-k)^2=r^2 for the circle, four sign variations of y^2=4ax for the parabola, and \dfrac{x^2}{a^2}\pm\dfrac{y^2}{b^2}=1 for the ellipse and hyperbola (the ± being the only difference between them algebraically, despite very different shapes). The Miscellaneous Exercise closes the chapter by putting these same equations to work in physical settings — a satellite dish, an arch bridge, a suspension cable, a racecourse — where the real skill is recognising which conic a situation is describing.

How the Chapter Builds

One Curve Leads to the Next

1

Circle

Fixed distance from a centre — the simplest conic. Exercise 10.1.

2

Parabola

Equidistant from a focus and a directrix — four standard orientations. Exercise 10.2.

3

Ellipse

Constant sum of distances to two foci — eccentricity always less than 1. Exercise 10.3.

4

Hyperbola

Constant difference of distances to two foci — eccentricity always greater than 1. Exercise 10.4.

Quick Reference

Important Formulas — Chapter 10

Everything you need before you start solving. This is a summary for quick recall — the Formula Cards below has the full printable version for all of Conic Sections.

Circle (§10.3)

Standard equation of a circle

(x-h)^2+(y-k)^2=r^2

Centre (h, k), radius r. Every point on the circle is at distance r from the centre.

Recovering centre and radius

x^2+y^2+2gx+2fy+c=0

Complete the square in x and y to rewrite in standard form and read off (h, k) and r.

Parabola (§10.4)

Standard equation (opens right)

y^2=4ax

Vertex at origin, focus (a, 0), directrix x = −a. The other 3 orientations flip the sign or swap x and y.

Latus rectum

\text{Length}=4a

The chord through the focus, perpendicular to the axis, with both ends on the parabola.

Ellipse (§10.5)

Standard equation

\dfrac{x^2}{a^2}+\dfrac{y^2}{b^2}=1

Major axis along whichever axis has the larger denominator (called a²); the smaller is b².

a, b, c relationship

c^2=a^2-b^2, \quad e=\dfrac{c}{a}<1

Foci lie inside the curve, at distance c from the centre; eccentricity is always less than 1.

Latus rectum

\text{Length}=\dfrac{2b^2}{a}

The chord through either focus, perpendicular to the major axis, with both ends on the ellipse.

Hyperbola (§10.6)

Standard equation

\dfrac{x^2}{a^2}-\dfrac{y^2}{b^2}=1

Transverse axis along whichever variable has the positive term.

a, b, c relationship

c^2=a^2+b^2, \quad e=\dfrac{c}{a}>1

Foci lie outside the curve; the "+" here (vs. the ellipse's "−") is what makes e always greater than 1.

Latus rectum

\text{Length}=\dfrac{2b^2}{a}

Same formula as the ellipse, measured through either focus perpendicular to the transverse axis.

Decision Guide

Which Conic Section Applies?

A quick way to decide, once you know what the question is actually describing.

What the question describesUse thisWhy
Points at a fixed distance from one fixed pointCircleThe defining condition is a constant radius from the centre (§10.3).
Points equidistant from a fixed point and a fixed lineParabolaMatch the sign and which variable is squared to pick the right of 4 standard forms (§10.4).
Sum of distances to two fixed points stays constantEllipseThe larger denominator in the equation tells you which axis is the major axis (§10.5).
Difference of distances to two fixed points stays constantHyperbolaOnly one of the two squared terms is positive; that variable's axis is the transverse axis (§10.6).
Equation not yet in standard form (extra constant, mixed terms)Complete the square / divide throughRewrite first, then read off centre/vertex/foci — don't try to read values off a non-standard equation (§10.3–10.6).
Given vertices/foci/axis lengths, asked for the equationSolve for a, b (or c) firstUse whichever relationship applies (c²=a²−b² for ellipse, c²=a²+b² for hyperbola) before writing the final equation.
A reflector, arch, bridge cable or racecourse word problemIdentify the conic, then set up coordinatesPlace the vertex or centre at the origin, axis along a coordinate axis, and use one known point to solve for the constant (Misc. Exercise).
Avoid These

Common Mistakes to Avoid in This Chapter

Drawn from where students actually lose marks across all four exercises.

  • Mixing up c² = a² − b² (ellipse) with c² = a² + b² (hyperbola) — this single sign is the entire algebraic difference between the two curves; swapping it gives a nonsensical or wrong answer every time.
  • Forgetting to divide through to reach standard form — equations like 16x² + y² = 16 or 36x² + 4y² = 144 must be divided by the constant on the right before a, b can be read off directly.
  • Misidentifying the major or transverse axis — for an ellipse, it's whichever denominator is larger; for a hyperbola, it's whichever term is positive. Guessing based on which variable appears first is a common error.
  • Picking the wrong one of the 4 parabola forms — check both which variable is squared (determines the axis) and the sign of the other term (determines the opening direction) before writing the equation.
  • Forgetting the latus rectum formula changes — it's 4a for a parabola, but 2b²/a for an ellipse or hyperbola; using the wrong one is an easy slip under time pressure.
  • Assuming a completed-square circle equation has integer centre/radius — the arithmetic can produce fractions or surds; don't round or "simplify" a genuine √ answer to the nearest integer.
  • Not checking that b² comes out positive — in equations from two given points (common in the Ellipse and Hyperbola exercises), solving the system can produce an extraneous root where b² is negative; that root must be rejected.
Solve Chapter-Wise

Class 11 Maths NCERT Solutions Chapter 10 — Choose an Exercise

10.1

Exercise 10.1

Circle — writing the equation from centre and radius, and recovering both by completing the square · 15 questions

Solve Exercise 10.1 →
10.2

Exercise 10.2

Parabola — focus, axis, directrix, latus rectum, and finding the equation from given conditions · 12 questions

Solve Exercise 10.2 →
10.3

Exercise 10.3

Ellipse — foci, vertices, axes, eccentricity, latus rectum, and finding the equation from given conditions · 20 questions

Solve Exercise 10.3 →
10.4

Exercise 10.4

Hyperbola — foci, vertices, eccentricity, latus rectum, and finding the equation from given conditions · 15 questions

Solve Exercise 10.4 →
M

Miscellaneous Exercise

Real-world applications — reflectors, arches, bridge cables, sliding rods and racecourses · 8 questions

Solve Miscellaneous →

📐 Keep the Formulas Handy

Every formula for Conic Sections — plus every other Class 11 Maths chapter — in one printable PDF.

Get Formula Cards →
Common Questions

Frequently Asked Questions

Quick answers from Class 11 Maths NCERT Solutions Chapter 10, Conic Sections.

How many exercises are there in Chapter 10, Conic Sections?
There are four main exercises — 10.1 (Circle, 15 questions), 10.2 (Parabola, 12 questions), 10.3 (Ellipse, 20 questions) and 10.4 (Hyperbola, 15 questions) — plus a Miscellaneous Exercise of 8 questions covering real-world applications, totalling 70 questions.
What are the four conic sections and how are they defined geometrically?
A circle is the set of points at a fixed distance (the radius) from a fixed point (the centre). A parabola is the set of points equidistant from a fixed point (the focus) and a fixed line (the directrix). An ellipse is the set of points where the sum of the distances to two fixed points (the foci) is constant. A hyperbola is the set of points where the difference of the distances to two fixed points (the foci) is constant.
How is the eccentricity of an ellipse different from that of a hyperbola?
For both curves, eccentricity is defined as e = c/a. For an ellipse, c² = a² − b², so c is always less than a, making the eccentricity always less than 1. For a hyperbola, c² = a² + b², so c is always greater than a, making the eccentricity always greater than 1. A circle can be viewed as an ellipse with eccentricity 0.
How do you find the length of the latus rectum for a parabola versus an ellipse or hyperbola?
For a parabola y² = 4ax, the latus rectum has length 4a. For an ellipse or hyperbola with semi-major/transverse axis a and semi-minor/conjugate axis b, the latus rectum has length 2b²/a. In every case, the latus rectum is the chord through the focus, perpendicular to the axis, with both endpoints on the curve.
Where can I find the official NCERT textbook for this chapter?
Conic Sections is Chapter 10 of the NCERT Class 11 Mathematics textbook, published by the National Council of Educational Research and Training (NCERT) and prescribed by CBSE. You can download the official textbook PDF directly from ncert.nic.in, NCERT's official website — the solutions on this page follow the exercises exactly as they appear there.
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