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Chapter 21 of 31
Syllabus

Circles

Kerala Board · Class 12 · Mathematics

Complete topic list for Circles in Kerala Board Class 12 Mathematics. Key concepts, sub-topics, and what to focus on for board exams.

44 questions20 flashcards5 concepts
4 Topics · Kerala Board Class 12 Mathematics

Topics in Circles

1

Basic Definition and Standard Equation of Circle

  • A circle is the locus of all points equidistant from a fixed point (center)
  • Standard form: (x-h)² + (y-k)² = r² where center is (h,k) and radius is r
  • General form: x² + y² + 2gx + 2fy + c = 0 where center is (-g,-f) and radius is √(g²+f²-c)
2

Finding Circle Equations from Given Conditions

  • Circle through three non-collinear points: substitute coordinates and solve system of equations
  • Circle with given center and passing through a point: use distance formula for radius
  • Circle touching axes: special cases with center coordinates related to radius
3

Position of Point and Power of Point

  • Point P(x₁,y₁) relative to circle S = x² + y² + 2gx + 2fy + c = 0
  • S₁₁ < 0: point inside circle; S₁₁ = 0: point on circle; S₁₁ > 0: point outside circle
  • Power of point = S₁₁ = distance² from center - radius²
4

Tangent and Normal to Circle

  • Equation of tangent at point (x₁,y₁) on circle S = 0 is S₁ = 0
  • For circle x² + y² = r²: tangent at (x₁,y₁) is xx₁ + yy₁ = r²
  • Normal passes through center and point of contact

Key Concepts

A circle is the locusx² + y² + 2gx +Circle with centre (hFor circle S = x² +Tangent at point (x₁

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Frequently Asked Questions

What are the important topics in Circles for Kerala Board Class 12 Mathematics?

Circles covers several key topics that are frequently asked in Kerala Board Class 12 board exams. Focus on the core concepts listed on this page and practise related questions to build confidence.

Start by understanding all key concepts. Practise previous year questions from this chapter. Revise formulas and definitions regularly. Use flashcards for quick revision before the exam.

Sources & Official References

Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.