Lets have a look at some of the important formulas NCERT Class 9 Mathematics book for all the chapters.
CBSE Maths Formulas For Class 9 from NCERT Book
Chapter 1: Number Systems
1.
2.
3.
4.
5. Rationalizing Factor: For
6.
7.
8.
9.
10.
Chapter 2: Polynomials
1. For a polynomial
Degree = Highest power of
2. Remainder Theorem: If
3. Factor Theorem:
4. Algebraic Identities:
–
–
–
–
5. Cubic Identities:
–
–
–
–
Chapter 3: Coordinate Geometry
1. Distance Formula:
2. Midpoint Formula:
3. Section Formula (Internal Division):
4. Area of a Triangle:
Chapter 4: Linear Equations in Two Variables
1. General form of a linear equation in two variables:
where
2. Solution of a linear equation:
A pair
3. Equation of a straight line:
Chapter 5: Introduction to Euclid’s Geometry
(No specific formulas, but important postulates include:)
1. A straight line can be drawn from any point to any other point.
2. A terminated line can be produced indefinitely.
3. A circle can be drawn with any center and radius.
4. All right angles are equal.
5. If a straight line falling on two straight lines makes the interior angles on the same side less than two right angles, the two straight lines, if produced indefinitely, meet on that side.
Chapter 6: Lines and Angles
1. Angle Sum Property of a Triangle:
2. Vertically Opposite Angles:
3. Linear Pair Axiom:
4. Parallel Lines:
– Corresponding Angles:
– Alternate Interior Angles:
– Co-Interior Angles:
Chapter 7: Triangles
1. Pythagoras Theorem (for a right triangle):
2. Converse of Pythagoras Theorem:
3. Area of an Equilateral Triangle:
4. Heron’s Formula for Area of a Triangle:
5. Similar Triangles (Basic Proportionality Theorem):
If a line is drawn parallel to one side of a triangle to intersect the other two sides, it divides the two sides in the same ratio:
Chapter 8: Quadrilaterals
1. Sum of Interior Angles of a Quadrilateral:
2. Parallelogram Properties:
– Opposite sides are equal:
– Opposite angles are equal:
– Diagonals bisect each other:
3. Area of a Parallelogram:
4. Area of a Rhombus:
Chapter 9: Circles
1. Circumference of a Circle:
2. Area of a Circle:
3. Length of an Arc:
4. Area of a Sector:
Chapter 10: Heron’s Formula
1. Area of a Triangle (Heron’s Formula):
Chapter 11: Surface Areas and Volumes
1. Surface Area of a Sphere:
2. Volume of a Sphere:
3. Surface Area of a Hemisphere:
4. Volume of a Hemisphere:
5. Surface Area of a Cylinder:
6. Volume of a Cylinder:
7. Surface Area of a Cone:
8. Volume of a Cone: