Course Content
Theme 01: Rational and irrational number.
Theme 02: Compound interest
Theme 03: Expansions
Theme 04: Factorisation
Theme 05: Simultaneous linear equation
Theme 08: Indices
Theme 09: Logarithms
Theme 10: Triangles
Theme 11: Mid-point Theorems
The Midpoint Theorem is a fundamental concept in geometry that relates to the properties of line segments. In the ICSE Class 9 Mathematics curriculum, the Midpoint Theorem is typically covered as part of the chapter on Lines and Angles or Triangles. Here's a summary of the Midpoint Theorem: **Midpoint Theorem**: In a given line segment, the line segment joining the midpoints of the two sides is parallel to the third side and is half of its length. **Statement of the Theorem**: Let (AB) be a line segment and (M) be the midpoint of (AB). If (P) is any point on the line segment (AB), then (2 times PM = AB). **Proof of the Theorem**: The proof involves constructing a parallel line through (P) to (AB), intersecting (AM) and (BM) at points (N) and (O), respectively. Using the properties of parallel lines, it can be shown that (2 times PM = AB). **Application of the Theorem**: The Midpoint Theorem is used in various geometric proofs and constructions. It helps in understanding the relationship between the sides and diagonals of a triangle and is often used to prove other theorems related to triangles and quadrilaterals. **Example**: In a triangle (ABC), (D) is the midpoint of (BC). If (AD) is extended to (E) such that (DE = AD), prove that (AB = 2 times DE). **Conclusion**: The Midpoint Theorem is a fundamental concept in geometry that helps in understanding the properties of line segments and their relationships in geometric figures. It is a key theorem that forms the basis for many other theorems in geometry.
Theme 13: Rectilinear figures
In the ICSE Class 9 Mathematics syllabus, the topic of "Rectilinear Figures" typically covers various polygons and their properties. Here's a summary of the key concepts usually included in this topic: 1. **Polygon**: A polygon is a closed figure formed by three or more line segments. It is classified based on the number of sides it has. Examples include triangles, quadrilaterals, pentagons, etc. 2. **Types of Polygons**: - **Triangle**: A polygon with three sides. Classified based on angles as acute, obtuse, or right-angled triangles. - **Quadrilateral**: A polygon with four sides. Examples include square, rectangle, parallelogram, rhombus, trapezium, etc. - **Pentagon, Hexagon, etc.**: Polygons with five, six, or more sides, respectively. 3. **Properties of Rectilinear Figures**: - **Interior Angles**: The sum of interior angles of an n-sided polygon is (n-2) * 180 degrees. - **Exterior Angles**: The exterior angle of a polygon is equal to 360 degrees divided by the number of sides. - **Diagonals**: The number of diagonals in a polygon can be calculated using the formula: n(n-3)/2, where n is the number of sides. 4. **Special Types of Quadrilaterals**: - **Square**: A quadrilateral with all sides equal and all angles right angles. - **Rectangle**: A quadrilateral with opposite sides equal and all angles right angles. - **Parallelogram**: A quadrilateral with opposite sides parallel and equal. - **Rhombus**: A quadrilateral with all sides equal but not necessarily right angles. - **Trapezium**: A quadrilateral with one pair of parallel sides. 5. **Area and Perimeter**: - **Area**: The area of a polygon can be calculated using different formulas based on the type of polygon. - **Perimeter**: The perimeter is the sum of all the sides of the polygon. 6. **Application Problems**: Real-life problems involving the calculation of areas and perimeters of rectilinear figures. This summary provides a general overview of the topic "Rectilinear Figures" in the ICSE Class 9 Mathematics syllabus. Students are advised to refer to their textbooks and practice solving problems to master these concepts.
Theme 14: Theorems on area
In the ICSE Class 9 Mathematics curriculum, the topic of theorems on area typically covers various theorems and concepts related to the calculation of area in different geometric shapes. Here's a summary of the key theorems and concepts: 1. **Area of a Triangle**: The area of a triangle can be calculated using the formula A = 1/2 * base * height, where the base is the length of the triangle's base and the height is the perpendicular distance from the base to the opposite vertex. 2. **Area of a Parallelogram**: The area of a parallelogram is equal to the product of its base and height, i.e., A = base * height. 3. **Area of a Trapezium**: The area of a trapezium is equal to half the sum of the lengths of its parallel sides multiplied by the height, i.e., A = 1/2 * (a + b) * h, where 'a' and 'b' are the lengths of the parallel sides and 'h' is the height. 4. **Area of a Rhombus**: The area of a rhombus can be calculated as half the product of its diagonals, i.e., A = 1/2 * d1 * d2, where 'd1' and 'd2' are the lengths of the diagonals. 5. **Area of a Circle**: The area of a circle is given by the formula A = π * r^2, where 'r' is the radius of the circle and π (pi) is a constant approximately equal to 3.14159. 6. **Pythagoras Theorem**: In a right-angled triangle, the square of the length of the hypotenuse (the side opposite the right angle) is equal to the sum of the squares of the lengths of the other two sides. This can be written as a^2 + b^2 = c^2, where 'a' and 'b' are the lengths of the two shorter sides (legs) and 'c' is the length of the hypotenuse. These theorems and formulas are essential for calculating the areas of different geometric shapes and are foundational concepts in geometry and mathematics.
Theme 15: Circle
Theme 19: Coordinate Geometry
Mathematics – 9
About Lesson

In the ICSE Class 9 Mathematics curriculum, the topic of factorization is an important concept. Factorization involves breaking down a number or an algebraic expression into its factors. Here’s a summary of the key aspects covered in this topic:


1. **Factors**: Factors are numbers or algebraic expressions that divide another number or expression without leaving a remainder. For example, the factors of 12 are 1, 2, 3, 4, 6, and 12.


2. **Prime and Composite Numbers**: A prime number is a number that has exactly two factors: 1 and itself. A composite number has more than two factors. Understanding prime and composite numbers is essential for factorization.


3. **Prime Factorization**: Prime factorization is the process of expressing a composite number as a product of its prime factors. For example, the prime factorization of 24 is 2 x 2 x 2 x 3, or 2^3 x 3.


4. **Factorization of Algebraic Expressions**: In algebra, factorization involves expressing algebraic expressions as a product of their factors. This is often done to simplify expressions and solve equations.


5. **Methods of Factorization**: There are various methods for factorizing algebraic expressions, including:


   – Common Factor Method: Identifying and factoring out the common factors in an expression.

   – Factorization by Grouping: Grouping terms in an expression and then finding common factors.

   – Factorization of Quadratic Expressions: Factoring quadratic expressions of the form ax^2 + bx + c using methods like splitting the middle term or the formula method.


6. **Applications**: Factorization is used in various mathematical concepts and real-life problems, including simplifying expressions, solving equations, and finding the roots of polynomial equations.


Mastering factorization is crucial for understanding more advanced topics in mathematics, such as algebra, number theory, and calculus. It is a fundamental skill that helps in problem-solving and understanding the structure of numbers and algebraic expressions.