CBSE Revision Notes

Circles Class 9 CBSE Math Notes: Chapter 11

Circles Class 9 Notes for circles provided here will help students study everything about the concept from properties of a circle to other related terms. In these notes, students will also find important theorems, questions, and exercises which will be extremely helpful in preparing for the exam. Students will find some of the topics discussed in the chapter below;

• Definition of a circle.
• Related terms like Chord, Diameter, Circumference, Arc, Sector, Radius, and Segment.
• Important Questions.

Areas Of Parallelograms And Triangles Class 9 Notes: Chapter 10

Areas of Parallelograms and Triangles Class 9 Notes are provided here so that students can study effectively and complete the entire revision of chapter 9 and the topics before the exams. The notes provided here contain clear and concise explanations of the concepts and will help students perform better in the exams. Some of the important topics covered in chapter 9 notes include;

• Introduction to areas of parallelograms and triangles.
• Figures on the same base and between the same parallels.
• Parallelograms on the same base and between the same parallels.
• Triangles on the same base and between the same parallels.
• Examples.
• Important questions.

Quadrilaterals Class 9 Notes – Chapter 9

What is a quadrilateral?
A quadrilateral is a closed figure with four straight sides. The sum of all the interior angles of a quadrilateral is 360 degree. Quadrilaterals Class 9 Notes are provided here to help learners prepare for their examination in an easy and effective manner.

The diagonal splits a parallelogram into 2 triangles which are congruent. Opposite sides and angles of a parallelogram are equal. Also, diagonals of a parallelogram always bisecting each other.

• A quadrilateral is a parallelogram, if either opposite sides or opposite angles are equal or diagonals are bisecting each other or pair of opposite sides are parallel and equal.
• In a rectangle, diagonals are equal and bisect each other and vice-versa.
• In a rhombus, diagonals bisect each other at 90 degree and vice-versa.
• In a square, diagonals are equal and bisect each other at 90 degree and vice-versa.
• In a triangle, the line joining midpoints of any two sides is parallel to the 3rd side and is half of it.

Linear Equations in Two Variables Class 9 Notes – Chapter 8

Each linear equation in two variables can be defined in a straight line. To solve a system of two linear equations in two variables, we graph both equations in the same coordinate system. The equation that can be represented in the form of px + qy + r = 0 is called a two variable linear equation. [where p, q & r are real, and p & q are not 0]. For example: 2.5p + 3q = 9, x + 8y = 9, 9u – 15v = 19, etc. Linear Equations in Two Variables Class 9 Notes are provided here to help learners understand the concepts of this chapter in an easy manner.

Heron’s Formula Class 9 Notes: Chapter 7

Heron’s Formula Class 9 Notes provided here will be a handy tool for students as it will help them understand the concept clearly and gain insight into the important questions given in the chapter. With these notes, students can further increase the possibility of scoring higher marks in the exams. Chapter 12 deals with topics like;

• Introduction To Heron’s Formula.
• Area of Triangle Formula.
• Application of Heron’s Formula in Finding Areas of Quadrilaterals.
• Examples.
• Important Questions.

Coordinate Geometry Class 9 Notes – Chapter 6

Coordinate geometry is the branch of geometry, where the position of the points on the plane is defined with the help of an ordered pair of numbers known as coordinates. Coordinate Geometry Class 9 Notes are provided here to help learners understand the concept in an easy manner.

Triangles Class 9 Notes – Chapter 5

We can define a triangle as a plane figure with three straight sides and three angles. Triangles Class 9 Notes is provided here to help students understand the concepts of this chapter in an easy and effective way.

Lines and Angles Class 9 – Chapter 4

What are line segment and a ray?
A line segment is a portion of a line with two endpoints whereas a ray is a line with just one endpoint. Three or more points are said to be collinear points if they lie on the same straight line. In all other conditions, the points will be termed as non-collinear points.  Lines and Angles Class 9 Notes discusses these concepts in a detailed manner.

What is an angle?
An angle is formed when 2 rays originate from the same point. There are basically 5 types of angles:

1. Acute Angle
2. Obtuse Angle
3. Right Angle
4. Reflex Angle
5. Straight Angle

Introduction to Euclid’s Geometry Class 9 Notes: Chapter 3

What is Euclid’s Geometry?
The word “geometry” comes from the Greek words “geo”, which means the “earth”, and “metrein”, which means “to measure”. Euclidean geometry is a mathematical system attributed to Euclid a teacher of mathematics in Alexandria in Egypt. Euclid gave us an exceptional idea regarding the basic concepts of geometry, in his book called “Elements”.

Euclid listed 23 definitions in his book “Elements”. Some important points are mentioned below:

• A line is an endless length.
• A point is one that which has no part.
• A line which lies evenly with the points on itself is a straight line.
• Points are the ends of a line.
• A surface is that which has breadth and length only.
• A plane surface is a surface which lies evenly with the straight lines on itself.
• Lines are the edges of a surface.

Euclid realized that a precise development of geometry must start with the foundations. Euclid’s axioms and postulates are still studied for a better understanding of geometry. Please refer  Introduction to Euclid’s Geometry Class 9 Notes for more revision notes.

Polynomial Class 9 Notes – Chapter 2

Polynomial comes from the word “poly” which means “many” and the word “nomial” which means “term”. In maths, a polynomial expression consists of variables which are also known as indeterminates and coefficients. The coefficients involve the operations of subtraction, addition, non-negative integer exponents of variables and multiplication. A detailed Polynomials Class 9 Notes are provided here along with some important questions so that students can understand the concept in an easy manner.