Mathematics Class 9

Inequalities PDF Download PDF

Co-ordinate Geometry is the branch of mathematics in which algebraic methods are used to solve geometrical problems. Two perpendicular number lines intersecting at point zero are called coordinate axes. The horizontal number line is the x-axis (denoted by X’OX) and the vertical one is the y-axis (denoted by Y’OY). The point of intersection of the

The perimeter of a plane figure is the length of its boundary. The unit of the perimeter is the same as the unit of length, i.e. cm, m, mm, etc. The area of a plane figure is the measure of the surface enclosed by its boundary. The unit of area is cm2, m2, mm2, etc

The amount of surface enclosed by the boundary of a plane closed figure is called its area and is measured in squared units. A diagonal of a parallelogram divides it into two congruent triangles i.e. two triangles of equal area. Parallelograms between the same base and between the same parallels are equal in area. A

Pythagoras theorem: In a right-angled triangle, the square of the hypotenuse is equal to the sum of the squares of the remaining two sides. Converse of Pythagoras theorem: If, in any triangle, the square of the longest side is equal to the sum of the squares of the remaining two sides, then the triangle is

An isosceles triangle is a triangle in which two sides have the same length. An equilateral triangle is a triangle in which all three sides are equal in length. All equilateral triangles are isosceles triangles and all isosceles triangles are not equilateral triangles. Isosceles Triangle PDF Download PDF

Power is the product of a number by itself. It is represented by a base number and an exponent. An index is a number that indicates how many times another number, the base, is being used as a repeated factor. Indices PDF Download PDF

An equation that is true for all values of its variables is called an identity. Expansions PDF Download PDF

Important Concepts of Compound Interest Compound Interest PDF Download PDF

Trigonometry is the study of the relationship between the sides and the angles of the triangle. The word trigonometry is derived from the Greek words ‘tri’ meaning three, ‘gon’ meaning sides, and ‘metron’ meaning measure. The angle measured in an anticlockwise direction is taken as the positive angle. The angle measured in a clockwise direction