Skip to main content
Super TutorResources
Chapter 7 of 9
QuestionsNotesFlashcardsSummaryFormulasQuizConceptsSyllabusPlan
Revision Notes

Mensuration

Tamil Nadu Board · Class 9 · Mathematics

Quick revision notes for Mensuration — Tamil Nadu Board Class 9 Mathematics. Key concepts, formulas, and definitions for last-minute revision.

44 questions25 flashcards5 concepts

Interactive on Super Tutor

Studying Mensuration? Get the full interactive chapter.

Quizzes, flashcards, AI doubt-solver and a step-by-step study plan — built for revision notes and more.

Try Super Tutor — Free

1,000+ Class 9 students started this chapter today

Key Topics to Revise

1

7.1 - 7.2: Heron's Formula and Triangle Areas

  • Heron's Formula is used when the height of a triangle is unknown but all three sides are given
  • Semi-perimeter (s) is half the perimeter: s = (a + b + c)/2
  • Area = √[s(s-a)(s-b)(s-c)] square units
2

7.3: Heron's Formula for Quadrilaterals

  • To find the area of a quadrilateral using Heron's formula, divide it into two triangles using a diagonal
  • Method: Draw a diagonal to create two triangles, calculate area of each using Heron's formula, then add them
  • Area of Quadrilateral ABCD = Area of Triangle ABC + Area of Triangle ACD (when divided by diagonal AC)
3

7.4: Surface Area of Cuboids and Cubes

  • Cuboid: A 3D solid with 6 rectangular faces, 12 edges, and 8 vertices; defined by length (l), breadth (b), and height (h)
  • Cube: Special cuboid where l = b = h; all faces are squares
  • Total Surface Area (TSA): Sum of areas of all 6 faces
4

7.5: Volume of Cuboids and Cubes

  • Volume: The measure of space occupied by a 3D solid, expressed in cubic units (cm³, m³, etc.)
  • Volume = Base Area × Height
  • For Cuboid: V = l × b × h (length × breadth × height)

Get complete notes with diagrams and examples

Full Notes

Key Concepts

Heron's formula allows calculating the areaThe semiA quadrilateral can be divided intoA cuboid is a threeTSA is the sum of areas

Frequently Asked Questions

What are the important topics in Mensuration for Tamil Nadu Board Class 9 Mathematics?
Key topics in Mensuration include Pie chart showing distribution of mensuration applications across different industries, Flowchart showing verification steps to avoid common mistakes, Comprehensive mind map summarizing all key formulas from the chapter. These are the concepts Tamil Nadu Board Class 9 examiners draw on most — study them first, then practise related questions.
How to score full marks in Mensuration — Tamil Nadu Board Class 9 Mathematics?
Understand the core concepts first, then work through the 44 practice questions available for this chapter. Revise formulas and definitions regularly, and use flashcards for quick recall before the exam.

Sources & Official References

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

More resources for Mensuration

All 9 chapters — Tamil Nadu Board Class 9 Mathematics Revision Notes

For serious students

Get the full Mensuration chapter — for free.

Quizzes, flashcards, AI doubt-solver and a step-by-step study plan for Tamil Nadu Board Class 9 Mathematics.

Try Super Tutor Free
Try the full chapter — Free