Triangle and its Various Kinds of Centres for Competitive Exams

A triangle is a three-sided polygon with three vertices and three edges. Triangles can be classified based on their angles as acute (all angles less than 90 degrees), right (one 90 degree angle), or obtuse (one angle more than 90 degrees). They can also be classified based on their sides as equilateral (all sides equal), isosceles (two sides equal), or scalene (no sides equal). The "various kinds of centres" refer to special points within a triangle that have unique geometric properties.

Centre Description
Centroid Intersection of medians. Divides medians in 2:1 ratio.
Orthocenter Intersection of altitudes. Lies inside acute triangles, at vertex of right triangles, outside obtuse triangles.
Circumcenter Centre of circumcircle passing through vertices.
Incenter Centre of incircle touching sides.
Excenters Centres of excircles touching one side and extensions of other sides.

Key Syllabus Areas

The SSC CGL syllabus covers:

  • Construction and identification of triangle centers.
  • Relationships between lengths of medians, altitudes, radii.
  • Applying relationships to calculate area, perimeter, angles.
  • Theorems like Stewart's and Ptolemy's.

Developing Mastery of the Topic

Mastering this topic requires:

  • Strong grasp of basic triangle properties.
  • Visualizing construction of centers in different triangles.
  • Practicing application of formulas/theorems.
  • Understanding concepts rather than just memorizing.

Key Resources

Useful resources include:

  • NCERT Mathematics textbooks of Classes 6-8.
  • SSC CGL Quantitative Aptitude reference books.
  • Online tutorials and videos.
  • Practice mocks and previous year papers.

Tips for Exam Preparation

  • Focus on conceptual clarity not just formulas.
  • Strengthen basics of triangle properties.
  • Practice visualizing and constructing various centers.
  • Apply concepts to solve examples and previous papers.
  • Take timed mocks to build speed and accuracy.


With strong fundamentals, structured practice, and a conceptual approach, mastering "Triangle and its Various Kinds of Centres" for SSC CGL Tier-I is very much achievable. This guide equips you with the key knowledge areas, preparation strategies, and resources to tackle all triangle-based questions with ease.


Q1: What are the important triangle centers to know for SSC CGL?

A1: The key triangle centers to know are centroid, orthocenter, circumcenter, incenter and excenters.

Q2: How can I develop conceptual clarity on this topic?

A2: Focus on understanding concepts rather than merely memorizing formulas. Refer to NCERT books and study visual representations.

Q3: What kind of practice questions should I solve?

A3: Practice a mix of diagram-based conceptual questions and numerical calculation-based formulas questions.

Q4: Should I memorize all the formulas related to triangle centers?

A4: Instead of outright memorization, derive formulas from concepts and practice applicating them.

Q5: How can I develop speed and accuracy?

A5: Take mocks within the exam time limit. Analyze your errors and weaknesses. Improve those areas through targeted practice.

Q6: Which resources are most important for this topic?

A6: The NCERT textbooks, SSC CGL quantitative aptitude books, online tutorials and previous year papers.