Class 9 Mathematics Revision Notes
Number Systems Notes
Number Systems — Notes Rational and irrational numbers A rational number can be written as ( integers, ). Its decimal expansion is terminating or non terminating recurring . An ir…
Polynomials Notes
Polynomials — Notes A polynomial in one variable is an expression with whole number powers of . Degree and types The highest power is the degree . By degree: linear (1), quadratic…
Coordinate Geometry Notes
Coordinate Geometry — Notes The Cartesian plane Two perpendicular number lines — the horizontal x axis and vertical y axis — meet at the origin and divide the plane into four quad…
Linear Equations in Two Variables Notes
Linear Equations in Two Variables — Notes A linear equation in two variables has the form , where and are not both zero. Solutions A solution is a pair that satisfies the equation…
Lines and Angles Notes
Lines and Angles — Notes Pairs of angles A linear pair of adjacent angles is supplementary (sum ). Vertically opposite angles (formed by two intersecting lines) are equal. The sum…
Triangles Notes
Triangles — Notes Congruence of triangles Two triangles are congruent if their corresponding sides and angles are equal. The criteria are: SAS, ASA, AAS, SSS , and RHS (for right…
Quadrilaterals Notes
Quadrilaterals — Notes Angle sum The sum of the interior angles of a quadrilateral is . Properties of a parallelogram Opposite sides are equal and parallel; opposite angles are eq…
Circles Notes
Circles — Notes A circle is the set of all points at a fixed distance (radius) from a fixed point (centre). Chords Equal chords subtend equal angles at the centre, and are equidis…
Heron's Formula Notes
Revision notes for Heron's Formula in Class 9 Mathematics, covering every key concept and term.
Surface Areas and Volumes Notes
Surface Areas and Volumes — Notes Solids and their formulas Cuboid: TSA ; Volume . Cube: TSA ; Volume . Cylinder: CSA ; TSA ; Volume . Cone: CSA ; TSA ; Volume , with slant . Sphe…
Statistics Notes
Statistics — Notes Statistics deals with collecting, presenting and interpreting data. Presentation of data Data is organised into frequency distribution tables (ungrouped or grou…