Difference between revisions of "Triangles"

From Karnataka Open Educational Resources
Jump to navigation Jump to search
Line 168: Line 168:
  
 
Create a new page and type <nowiki>{{subst:Math-Content}}</nowiki> to use this template
 
Create a new page and type <nowiki>{{subst:Math-Content}}</nowiki> to use this template
 
 
== Enrichment    Activities ==
 
 
 
=== Activity 2 Similar Triangles ===
 
 
'''Learning Objective'''
 
 
 
To show similar planar
 
figures, discuss congruence and properties of congruent/ similar
 
triangles
 
 
 
 
 
 
==== Material and Resources Required ====
 
 
Blackboard
 
 
 
Geogebra files +
 
projector
 
 
 
Calculator
 
 
 
 
'''[[Pre-requisites/Instructions]] '''
 
 
 
* Planar figures and triangles
 
* Draw pairs of figures on the board [ both similar and dissimilar]; they can identify overlap of congruent figures
 
* Ask the children to identify
 
* If the children know the names of the theorem, ask them to explain- ask them what is SSS, AAA, ASA
 
* Show ratio and give the idea of proportionality
 
* Geogebra files. When I change the sides/ proportion, the triangles change in size. But the proportion remains the same, angle remains the same
 
* With calculator they verify proportion (this is very very useful for involving the whole class) they all can see the proportion remains constant though the size changes
 
* Show the arithmetic behind the proportion
 
 
==== Evaluation ====
 
 
[Activity evaluation -
 
What should the teacher watch for when you do the activity; based on
 
what they know change]
 
 
 
* Confusion between congruence and similarity
 
* When they give the theorem, if they cannot identify included side and angle
 
* When there is a wrong answer, identify what is the source of the confusion – sides, ratio and proportion
 
 
* Direct substitution
 
 
== Evaluation ==
 
 
== Self-Evaluation ==
 
 
== Further Explorations ==
 
 
== Enrichment Activities ==
 
 
= Pythagorean Theorem =
 
 
Pythagoras' Theorem was discovered by
 
Pythagoras, a Greek mathematician and philosopher who lived
 
between approximately 569 BC and 500 BC.
 
 
 
Pythagoras'
 
Theorem states that:
 
 
 
In
 
any right-angled triangle, the square of the hypotenuse is equal
 
to the sum of the squares of the other two sides. That is:
 
 
 
[[Image:KOER%20Triangles_html_m2f096af4.png]]
 
 
 
[[Image:KOER%20Triangles_html_4bd439df.png]]
 
 
 
 
 
'''Pythagoras' Theorem in
 
Three Dimensions'''
 
 
 
A
 
three-dimensional object can be described by three measurements -
 
length, width and height.
 
 
 
[[Image:KOER%20Triangles_html_679fe2f6.png]][[Image:KOER%20Triangles_html_m570261d2.png]]
 
 
 
We
 
can use Pythagoras' Theorem to find the length of the longest
 
straw that will fit inside
 
 
 
the
 
box or cylinder.
 
 
 
== Evaluation ==
 
 
== Self-Evaluation ==
 
 
== Further    Explorations ==
 
 
 
== Enrichment    Activities ==
 
 
= See    Also =
 
 
 
 
 
 
 
 
 
 
= Teachers    Corner =
 
 
Suchetha . S. S  Asst. Teacher ( Mathematics ) GJC Thyamagondlu. Nelamangala Talluk Bangalore Rural District doing a lesson on similar triangles using GeoGebra in the classroom
 
 
[[Image:KOER%20Triangles_html_m3d25043b.jpg|600px]]
 
 
 
== GeoGebra Contributions ==
 
# The GeoGebra file below to understand Similar Triangles <br>
 
## Similar Triangles Part 1 http://www.karnatakaeducation.org.in/KOER/Maths/Similar_Triangles_1.html
 
## Download ggb file here http://www.karnatakaeducation.org.in/KOER/Maths/Similar_Triangles_1.ggb
 
## Similar Triangles Part 2 http://www.karnatakaeducation.org.in/KOER/Maths/Similar_Triangles_2.html
 
## Download ggb file here http://www.karnatakaeducation.org.in/KOER/Maths/Similar_Triangles_2.ggb
 
## Similar Triangles Part 3 http://www.karnatakaeducation.org.in/KOER/Maths/Similar_Triangles_3.html
 
## Download ggb file here http://www.karnatakaeducation.org.in/KOER/Maths/Similar_Triangles_3.ggb
 
## See a video to understand this concept http://www.youtube.com/watch?v=BI-rtfZVXy0
 
 
# The GeoGebra file below verifies the Thales theorem <br>
 
## Thales Theorem http://www.karnatakaeducation.org.in/KOER/Maths/thales_theorem.html
 
## Download ggb file here http://www.karnatakaeducation.org.in/KOER/Maths/thales_theorem.ggb
 
## See a video that proves this theorem http://www.youtube.com/watch?v=Y-6yYsuGLoc
 
 
= Books =
 
 
 
 
 
 
= References =
 

Revision as of 07:19, 6 December 2013

The Story of Mathematics

Philosophy of Mathematics

Teaching of Mathematics

Curriculum and Syllabus

Topics in School Mathematics

Textbooks

Question Bank

While creating a resource page, please click here for a resource creation checklist.

Concept Map

Error: Mind Map file 5._Triangles.mm not found



Textbook

To add textbook links, please follow these instructions to: (Click to create the subpage)

Additional Information

Useful websites

  1. All about triangles

This is a reference website for types and classification off triangles

Reference Books

Teaching Outlines

Concept #1 What is a triangle

Learning objectives

  1. Triangle is a polygon
  2. Sides and angles determine the type of triangle
  3. The relationship between sides and angles of triangle

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.

Triangle is the most basic polygon shape. Triangles are classified on the basis of their angles and sides.

Click here for notes on types of triangles.

Activity No #1 - Make your triangle

  • Estimated Time - 40 minutes
  • Materials/ Resources needed
  • Prerequisites/Instructions, if any
  • Multimedia resources
  • Website interactives/ links/ Geogebra Applets
  • Process (How to do the activity)

Mark three non-collinear point P, Q and R on a paper. Join these points in all possible ways. The segments are PQ, QR and RP. A simple close curve formed by these three segments is called a triangle. It is named in one of the following ways.

Triangle PQR or Triangle PRQ or Triangle QRP or Triangle RPQ or Triangle RQP .

picture of equilateral triangle PQR

  • Developmental Questions (What discussion questions)

A triangle is one of the basic shapes of geometry: a polygon with three corners or vertices and three sides or edges which are line segments. In fact, it is the polygon with the least number of sides.

A triangle PQR consists of all the points on the line segment PQ,QR and RP. The three line segments, PQ, QR and RP that form the triangle PQ, are called the sides of the triangle PQR.

How many angles? A triangle has three angles. In figure, the three angles are ∠PQR ∠QRP and ∠RPQ A triangle has six parts, namely, three sides,PQ QRand RP.Three angles ∠PQR ∠QRP and ∠RPQ. These are also known as the elements of a triangle.

What are the intersection points of line segments? The point of intersection of the sides of a triangle is known as its vertex. In figure, the three vertices are P, Q and R. In a triangle, an angle is formed at the vertex. Since it has three vertices, so three angles are formed. The word triangle =tri + angle ‘tri’ means three. So, triangle means closed figure of straight lines having three angles.


  • Evaluation (Questions for assessment of the child)
  • Question Corner

Activity No # 2 - Types of triangles - Identifying and naming

Part 1

  • Estimated time - 20 minutes
  • Materials/ Resources needed
  • Prerequisites/Instructions, if any
  • Multimedia resources

KOER Triangles html m27d3a9c5.png

  • Website interactives/ links/ Geogebra Applets
  • Process (How to do the activity)

Identify and name the triangles in the above figure.

  • Evaluation
  1. Is it possible to construct a triangle with 3 collinear points?
  2. Is it possible to construct a triangle whose sides are 3cm, 4cm and 9cm. Why?.

Part 2

  • Estimated time - 20 minutes
  • Materials/ Resources needed
  • Prerequisites/Instructions, if any
  • Multimedia resources

Look at the following images below

Equilateral Triangle Isosceles triangle Scalene triangle
Right triangle Obtuse triangle Acute triangle
  • Website interactives/ links/ Geogebra Applets
  • Process (How to do the activity)

Identify and name the triangles in the above figure.

  • Evaluation
  1. Can a scalene triangle also be a right-angled triangle ? If yes can you draw one ?

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

Usage

Create a new page and type {{subst:Math-Content}} to use this template