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Classwise Concept with Examples
6th 7th 8th 9th 10th 11th 12th

Class 9th Chapters
1. Number Systems 2. Polynomials 3. Coordinate Geometry
4. Linear Equations In Two Variables 5. Introduction To Euclid’s Geometry 6. Lines And Angles
7. Triangles 8. Quadrilaterals 9. Areas Of Parallelograms And Triangles
10. Circles 11. Constructions 12. Heron’s Formula
13. Surface Areas And Volumes 14. Statistics 15. Probability

Class 9 Mathematics: Concepts and Examples

Chapter 1 Number Systems

This chapter covers the different types of numbers such as natural numbers, whole numbers, integers, rational numbers, and real numbers. It also introduces the concept of irrational numbers and their properties, along with operations on real numbers.

Chapter 2 Polynomials

Students learn about algebraic expressions with more than one term, known as polynomials. The chapter covers the degree of polynomials, the different types of polynomials (monomials, binomials, trinomials), and the operations of addition, subtraction, and multiplication on polynomials.

Chapter 3 Coordinate Geometry

This chapter introduces the Cartesian coordinate system, where points are represented by pairs of numbers (x, y). Students learn how to plot points, find distances between two points, and understand the concept of the midpoint of a line segment.

Chapter 4 Linear Equations in Two Variables

Students learn about linear equations of the form ax + by = c, where a, b, and c are constants. The chapter focuses on solving these equations by various methods such as graphical and substitution methods, and their applications.

Chapter 5 Introduction to Euclid’s Geometry

This chapter introduces the basic concepts of geometry, as described by Euclid, including points, lines, angles, and planes. Students learn about Euclid's five postulates and theorems that form the foundation of geometry.

Chapter 6 Lines and Angles

This chapter covers different types of angles such as complementary, supplementary, and adjacent angles. Students also learn the properties of parallel lines, theorems related to angles formed by a transversal, and angle sum property of triangles.

Chapter 7 Triangles

Students explore the properties of triangles, including the different types (equilateral, isosceles, and scalene). The chapter also includes congruence of triangles, theorems related to sides and angles, and criteria for triangle congruence (SSS, SAS, ASA, RHS).

Chapter 8 Quadrilaterals

This chapter covers the properties of various quadrilaterals, such as rectangles, squares, parallelograms, rhombuses, and trapeziums. Students learn to prove basic properties and theorems related to quadrilaterals.

Chapter 9 Areas of Parallelograms and Triangles

Students learn to calculate the area of parallelograms and triangles using formulas. The chapter includes proofs of these formulas and applications of the area in real-life contexts.

Chapter 10 Circles

This chapter covers the basic properties of circles, including the circumference, radius, diameter, and arcs. Students also learn the theorems related to the angles subtended by chords and tangents to circles.

Chapter 11 Constructions

Students learn geometric constructions using a compass, ruler, and protractor. The chapter includes constructing bisectors of angles and line segments, as well as constructing perpendiculars and parallel lines.

Chapter 12 Heron’s Formula

This chapter explains Heron’s formula for finding the area of a triangle when the lengths of all three sides are known. It includes derivation and application of the formula to solve real-world problems.

Chapter 13 Surface Areas and Volumes

Students learn to calculate the surface area and volume of various 3D shapes, including cubes, cuboids, spheres, cones, and cylinders. The chapter introduces the necessary formulas for each shape.

Chapter 14 Statistics

This chapter introduces the collection, organization, and representation of data. Students learn to calculate measures like mean, median, mode, and range, and represent data using histograms and frequency polygons.

Chapter 15 Probability

Students are introduced to the concept of probability, which measures the likelihood of an event occurring. The chapter covers simple problems on probability and its applications in real-life situations.

These chapters equip students with the foundational concepts of mathematics, helping them build problem-solving skills and prepare for more advanced topics in mathematics.