Difference between revisions of "Quadrilaterals"
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====== [[Angle sum property of a quadrilateral]]====== | ====== [[Angle sum property of a quadrilateral]]====== | ||
| − | ====== Sum of the interior angles of a quadrilateral ====== | + | ====== [[Sum of the interior angles of a quadrilateral]] ====== |
| − | ====== Sum of angles at point of intersection of diagonals in a quadrilateral ====== | + | ====== [[Sum of angles at point of intersection of diagonals in a quadrilateral]] ====== |
| − | ====== Area of a quadrilateral ====== | + | ====== [[Area of a quadrilateral]] ====== |
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Revision as of 06:16, 2 May 2019
Concept Map
Additional Resources
OER
- List web resources with a brief description of what it contains; how it can be used and whether it can be by teacher/ student or both
- Books and journals
- Textbooks
- Syllabus documents
Non-OER
- List web resources with a brief description of what it contains; how it can be used and whether it can be by teacher/ student or both
- http://www.mathopenref.com/quadrilateral.html : Simple explanation about quadrilaterals.
- http://www.slideshare.net/muzzu1999/types-of-quadrilaterals-and-its-properties-group-4 : This website has a very good activity on properties of quadrilaterals.
- http://www.cimt.plymouth.ac.uk/projects/mepres/book8/bk8i1/bk8_1i3.htm This is a very good website for students to understand classification of quadrilaterals as per their properties.
- http://www.shodor.org/ihnteractivate/discussions/Quadrilaterals/ click here : For effective introduction to quadrilaterals.
- Books and journals
- Please download 9th standard mathematics textbook of Tamil Nadu state syllabus from the following link and refer the page 89 click here
- Refer 9th standard mathematics ncert textbook from the following link click here
- Textbooks : Karnataka State Text book of mathematics Class 9-Chapter 8:Quadrilaterals
- Syllabus documents (CBSE, ICSE, IGCSE etc)
Additional Information
An ortho-diagonal quadrilateral i.e., any quadrilateral whose diagonals are perpendicular to each other possesses certain interesting properties. This article 'Quadrilaterals with Perpendicular Diagonals' by Shailesh Shirali (published in 'At Right Angles' | Vol. 6, No. 2, August 2017) discusses a few of them.
Learning Objectives
- Introduction to polygons
- The meaning of quadrilateral
- Identification of various types of quadrilaterals
- Different properties of special quadrilaterals
- Construction of quadrilaterals to given suitable data
- Finding area of quadrilaterals
- Introduction to cyclic quadrilaterals
Teaching Outlines
Concept 1: Introduction to Quadrilaterals
The word quadrilateral comes from two latin words "quadri" which means a "variant of 4" and 'latera' which means 'side'. A quadrilateral is a 4 sided figure with 4 sides, 4 angles and 4 vertices.
This topic has its basics in polygons. Try to elicit live examples for quadrilaterals from within classroom, starting from the shape of a textbook. Show the vertices of a rectangular page. Mark three sets of four points on the blackboard, one set being collinear and other non-collinear. Call students to join the points of each set of points. This activity will introduce them to the concept of quadrilateral.
Activities #
Identifying quadrilaterals
Introduction to quadrilaterals
Concept 3: Types of quadrilaterals
Quadrilaterals are of different types. Grouping is made based on the four angle measures and/or sides. Each type is recognised with its characteristic properties. The types include regular, non-regular; convex, concave; parallelogram (square, rectangle, rhombus,) and non-parallelograms (trapezium and kite).
Activities #
"I have - Who has ?"
Venn diagrams of quadrilaterals
Concept 2: Properties of quadrilaterals
There are certain characteristic properties by which a quadrilateral is identified. A quadrilateral is a plane closed figure having 4 sides and 4 angles. The sum of all 4 interior angles of any quadrilateral always equals to 360 degrees.This is called interior angle sum property of a quadrilateral. The sum of all 4 exterior angles of any quadrilateral equals 360 degrees. This is called exterior angle sum property of the quadrilteral. The opposite angles of any quadrilateral are supplementary. If any 3 angles of a quadrilateral are known the fourth angle can be found using angle sum property.