Circle Formulas, Concepts, Strategies, Short Tricks, and Tips

Circle is one of the most important and frequently tested topics in geometry for competitive exams. In this blog, we have provided all the essential concepts, formulas, tricks, solved questions, and more.

What Is Circle in Quantitative Aptitude?

A circle is a set of all points in a plane that are equidistant from a fixed point called the center. The constant distance is called the radius.

Why it appears in exams:

  • Fundamental geometric shape with numerous properties.
  • Problems involve radius, diameter, chords, arcs, sectors, segments, and tangents.

Skills required:

  • Understanding geometric properties and relations.
  • Applying formulas related to circumference, area, arc length, and sector area.
  • Visualization of 2D figures.

Why Is Circle Important in Competitive Exams?

Circle problems test candidates’ understanding of basic geometric concepts and their ability to apply formulas for perimeter, area, arcs, and sectors, making it a valuable scoring topic.

ExamNo. of QuestionsDifficulty
SSC CGL / CHSL1–3Moderate
IBPS PO / SBI PO1–2Moderate
RRB NTPC / Group D1–2Easy
State PSC / Police1–2Moderate

Circle Quantitative Aptitude Short Notes

Terms mostly used to solve questions based on circles are as follows:

TermDetails
Radius (r)Distance from center to any point on the circle
Diameter (d)Twice the radius, longest chord in the circle
CircumferencePerimeter of the circle, calculated as 2πr2 \pi r2πr
AreaArea covered by the circle, calculated as πr2\pi r^2πr2
ChordA line segment connecting two points on the circle
ArcA part of the circumference
SectorThe area enclosed by two radii and an arc
SegmentThe area enclosed by a chord and its corresponding arc
TangentA line that touches the circle at exactly one point

Quick Circle Revision Summary

Here’s a handy summary of the most important formulas and facts about circles to aid quick memorization.

What Are the Types of Circle Questions in Quantitative Aptitude?

Circle problems can comes in various forms; knowing these types helps in quick recognition and solving.

  • Basic perimeter and area problems
  • Chord and segment length/area problems
  • Sector and arc length questions
  • Tangents and properties of tangents
  • Coordinate geometry related problems

Circle Formulas for Quantitative Aptitude

This section provides the essential formulas that help you solve circle-related problems accurately and quickly.

Circle Tricks for SSC CGL and Other Exams

Follow these tricks to solve circle problems efficiently in competitive exams:

  1. Remember π≈22/7​ or 3.14 for quick calculations.
  2. Use symmetry properties of circle to simplify problems.
  3. Visualize sectors and segments to avoid confusion between areas.
  4. In tangent problems, remember tangent is perpendicular to radius at point of contact.
  5. Practice applying formulas for arcs and sectors carefully by focusing on the angle subtended.

Solved Circle Questions from 2024–25 Exams

Common Mistakes to Avoid while Solving Circle Questions

Common mistakes that students must avoid while solving questions based on the topic of circles are as follows:

  • Using wrong value of π\piπ inconsistently.
  • Confusing chord length with arc length.
  • Forgetting to convert degrees in arc/sector formulas.
  • Mixing up sector and segment areas.
  • Not applying tangent-radius perpendicularity in tangent problems.

FAQs

Q1. What is the difference between arc and chord?

Arc is part of circumference, chord is a straight line between two points on circle.

Q2. What is a segment of a circle?

Area enclosed by a chord and the corresponding arc.

Q3. How is tangent related to radius?

Tangent is perpendicular to radius at point of contact.

Q4. Can the angle subtended by an arc be greater than 360°?

No, maximum is 360°.

Q5. What is the relation between radius and chord?

Radius bisects the chord if perpendicular.


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