Theorems On Triangles
| Philosophy of Mathematics |
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Concept Map
Textbook
Karnataka state textbook: Class 8, Chapter 12-Theorems on triangles
Additional Information
This videos is related to types of triangle based on angles and side respectively.
Useful websites
- To know about classification of triangleclick here
- To know about properties of triangleclick here
- To learn about angle sum property of the triangleclick here
- Get your students to recognise, use and communicate formally with one another about triangles and their properties, using conventional terminology, i.e., 'mathematical talk'. Click here
Reference Books
- TamilNadu text book for theorems on triangle click here page no 94-102
Teaching Outlines
Concept #introduction to triangles
Learning objectives
- Define triangle and classify different types of triangle based on sides and angles.
Notes for teachers
First teacher can talk about or try to elicit basic points of geometry like lines, collinear and non collinear point, vertices,sides ect. this leads to the triangle definition.Then by using activity try to classify triangle based on side and angles and name them. teacher can also try to elicit live examples for triangle which are seen in daily life. Teacher can use the inducto deductive or CAM method.
Activity No 1 # classification of triangle based on sides
- Estimated Time -30min
- Materials/ Resources needed
cut outs of triangle , scale, pencil
- Prerequisites/Instructions, if any
should know the meaning of triangle.and triangle is a 2 dimension figure
- Multimedia resources
laptop, geogebra file
- Website interactive/ links/ Geogebra Applets
- Process (How to do the activity)
- Divide the class into groups and provide materials for each group
- Ask them to measure the length of the each side of the given triangles.
- Help them to identify the 3 types of triangles in that given triangles.
- ask them to try to name the identified 3 different types of triangle.
- Developmental Questions (What discussion questions)
- what is the name of the given figure?
- how many types of triangle did you found?
- what name can you give for all this triangle?
- Evaluation (Questions for assessment of the child)
- on what basis we classify the triangle?
- Question Corner
Activity No 2 # Interior Angle Sum Property of a triangle
- Estimated Time-45 minutes
- Materials/ Resources needed
- chart paper, pencil, scale, protractor
- Prerequisites/Instructions, if any Students need to know:
- a triangle is a three sided polygon.
- types of triangles by sides and angles.
- the characteristics of triangles by sides and angles.
- facts of supplementary, adjacent and vertical angles.
- write and solve simple linear equations.
- Multimedia resources
- Laptop
- Website interactives/ links/ Geogebra Applets
- Geogebra file on interior angle sum of a triangle, Lighthouse (ck-12 series)
- Process (How to do the activity)
- Step 1- 1. On the piece of paper, use your pencil and ruler to draw a triangle. 2. Draw different types of triangles: Acute, Obtuse, or Right angled triangle. 3. Use a protractor to measure each angle of the triangle. 4. Label the interior of each angle. 5. Add all the angle measures together. What is the sum? 6. Cut out three angles from given triangles and rearrange the 3 “angles” so that their vertices meet at one point with no overlap. 7. Rearrange them to constitute one angle. What does this tell you about sum of the angles in the triangle?
- Developmental Questions (What discussion questions)
- Evaluation (Questions for assessment of the child)
- Question Corner
Concept #
Learning objectives
Notes for teachers
These are short notes that the teacher wants to share about the concept, any locally relevant information, specific instructions on what kind of methodology used and common misconceptions/mistakes.
Activity No #
- Estimated Time
- Materials/ Resources needed
- Prerequisites/Instructions, if any
- Multimedia resources
- Website interactives/ links/ Geogebra Applets
- Process (How to do the activity)
- Developmental Questions (What discussion questions)
- Evaluation (Questions for assessment of the child)
- Question Corner
Activity No #
- Estimated Time
- Materials/ Resources needed
- Prerequisites/Instructions, if any
- Multimedia resources
- Website interactives/ links/ Geogebra Applets
- Process (How to do the activity)
- Developmental Questions (What discussion questions)
- Evaluation (Questions for assessment of the child)
- Question Corner
Hints for difficult problems
Project Ideas
Math Fun
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