This is one of the most important sections for Grade 9 maths. There are a number of topics covered in this section:

- Introduction to Euclid’s Geometry
- Lines and Angles
- Triangles
- Quadrilateral
- Area of Triangles and Quadrilaterals
- Circles

Click on each topic to know more details.

Introduction to Euclid’s Geometry

Key topics include:

• Basic Geometric Concepts

• Some Terms Related to Geometry

• Line Segments

• Length Axioms of Line Segments

• Ray, Half-Life & Line Separation

• Incidence Properties of Points & Lines

• Parallel Lines & Intersecting Lines

• Euclid’s Five Postulates

• Basic Geometric Concepts

• Some Terms Related to Geometry

• Line Segments

• Length Axioms of Line Segments

• Ray, Half-Life & Line Separation

• Incidence Properties of Points & Lines

• Parallel Lines & Intersecting Lines

• Euclid’s Five Postulates

Lines and Angles

Key topics include:

• Point

• Line Segments

• Angles & Their Properties

• Types of Angles

• The Angle Bisector

• Angle Relations

• Parallel Line

Triangles

Key topics include:

- Triangles

- Definition

- Types of Triangles on the Basis of Sides

- Equilateral Triangle
- Isosceles Triangle
- Scalene Triangle
- Perimeter of a Triangle

- Types of Triangle on the Basis of Angles

- Right Angled Triangle
- Acute Angled Triangle
- Obtuse Angled Triangle

- Concurrent Lines & Various Centres of a Triangle

- Medians & Centroid
- Altitudes & Orthocentre
- Perpendicular Bisector of Sides & Circum-centre
- Angle Bisectors & In-Centre

- Theorems on Triangles

- Angle Sum Theorem (Theorem 1)
- External Angle Theorem (Theorem 2)
- Corollary of Theorem 2

Quadrilateral

Key topics include:

- Introduction
- Types of Quadrilateral
- Parallelogram
- Rectangle
- Square
- Rhombus
- Trapezium
- Kite

- Theorems on Quadrilaterals
- Theorems on Parallelograms

Area of Triangles and Quadrilaterals

Key topics include:

- Area Axioms
- Area of Polygonal Regions
- Base & Altitude of a Parallelogram
- Base
- Altitude

- Theorems on Triangles & Quadrilaterals

Circles

Key topics include:

• Basic Definitions

• Arcs of a Circle

• Sectors of a Circle

• Segments of a Circle

• Quadrants of a Circle

• Theorems on Circles

• Chords Properties of Circles

• Theorems on Congruent Circles

• Theorems on Angle Subtended by Arcs

• Theorems on Cyclic Quadrilateral

Read more about this course.

• Basic Definitions

• Arcs of a Circle

• Sectors of a Circle

• Segments of a Circle

• Quadrants of a Circle

• Theorems on Circles

• Chords Properties of Circles

• Theorems on Congruent Circles

• Theorems on Angle Subtended by Arcs

• Theorems on Cyclic Quadrilateral

Read more about this course.