Triangles
Concept Map
Additional Resources
OER
- Web resources:
- Wikipedia, the free encyclopedia : The website gives a comprehensive information on triangles from basics to in depth understanding of the topic.
- cbsemathstudy.blogspot.com : The website gives worksheets for the chapters that can be downloaded. Worksheets for other chapters can also be searched for which are listed based on class.
- Books and journals
- Textbooks
- NCERT Textbooks – Class 9
- Syllabus documents
Non-OER
- Web resources:
- Bright hub education : The website describes a lesson plan for introducing triangles and lists classroom problems at the end of the lesson that can be solved for better understanding.
- CPALMS : The website gives lesson plan, activities and worksheets associated with triangles.
- Books and journals
- Textbooks:
- Syllabus documents (CBSE, ICSE, IGCSE etc)
Learning Objectives
- Identifying a triangle and understanding its formation
- Recognizing all parameters related to triangles
- Understanding formation of triangles based on sides and angles
- Establishing relationship between parameters associated with triangles
Teaching Outlines
Concept 1: Formation of a triangle, elements of a triangle and its measures
Introducing formation of a shape with minimum number of lines and the space enclosed forms a geometric shape.The key geometric concepts that are associated with it and its properties are elaborated.
Activities
Formation of a triangle: A plane figure formed by three intersecting lines.
Elements and measures in triangle: Parameters that are associated and measured in a triangle.
Interior and exterior angles in triangle: Angles that are formed when a triangle is formed.
Concept 2: Types of triangles based on sides and angles
Triangles can be based on its elements such as sides and angles. Students are able to recognize these formations.
Activities
Types of triangles based on sides: Formation of a triangle depends on measures of sides.
Types of triangles based on angles: Formation of a triangle depends on measures of angles.
Concept 3: Theorems and properties
Properties of triangles are logically proved by deductive method. Relations ships between angles of a triangle when a triangle is formed are recognized and understood.
Activities
Angle sum property : Relation between angles formed inside a triangle
Exterior angle theorem: Relation between angles formed inside a triangles and angles outside a triangle
Concept 4: Construction of triangles
Constructing geometric shapes to precision using a scale and a compass helps in understanding of properties of the shape. Constructing geometric shapes with minimum number of parameters enhances thinking skills.
Elements of triangles are used in the following constructions where constructions are based on minimum number of parameters required.