Difference between revisions of "Polygons"
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# Because they all differ in the number of sides that they have, this results in different angle measures at their vertices. | # Because they all differ in the number of sides that they have, this results in different angle measures at their vertices. | ||
# With the exception of the triangle and quadrilateral, all polygon names end with "gon." | # With the exception of the triangle and quadrilateral, all polygon names end with "gon." | ||
− | # | + | # Generally polygons are named with their number of sides as prefixes. The prefix for the word "hexagon" is "hexa," which essentially means "six." |
==Notes for teachers== | ==Notes for teachers== |
Revision as of 10:20, 18 December 2013
Philosophy of Mathematics |
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Additional Information
Useful websites
1. http://www.wyzant.com/resources/lessons/math/geometry/quadrilaterals/polygons . This website is good for referring to the theory regarding polygons.
Reference Books
Teaching Outlines
- Introduction to polygon
- Naming the polygons
- Characteristics of polygons.
- Types of polygons.
Concept #1. Introduction to polygons and nomenclature.
Learning objectives
- Lines intersect to form figures.
- Two dimensional closed figures can be of varied shapes.
- Plane closed figures with ≥ 3 sides are known as polygons.
- They can be defined as two-dimensional, closed, plane shapes composed of a finite number of straight sides that meet at points called vertices.
- There are a countless number of polygons.
- Because they all differ in the number of sides that they have, this results in different angle measures at their vertices.
- With the exception of the triangle and quadrilateral, all polygon names end with "gon."
- Generally polygons are named with their number of sides as prefixes. The prefix for the word "hexagon" is "hexa," which essentially means "six."
Notes for teachers
Activity No # 1. Which polygon am I ?
- Estimated Time: 30 minutes.
- Materials/ Resources needed: Laptop, geogebra file, projector and a pointer.
- Prerequisites/Instructions, if any:
- The students should know that lines intersect to form figures.
- In other words plane closed figures have atleast 3 sides.
- The intersecting points of two lines is known as a vertex and the lines are the edges/sides.
- The student should know the meaning of greek numerals uni, bi, tri ....etc.
- Multimedia resources: Laptop
- Website interactives/ links/ / Geogebra Applets
- Process:
- The teacher can tell the students that they are surrounded by many different kinds of shapes every day.
- Many of these shapes are two-dimensional plane figures.
- Plane figures are flat. They can be closed or not closed.
- Plane figures made up of three or more closed line segments are polygons.
- Each line segment of a polygon is a side. Polygons are classified and named based on the number of sides.
- Developmental Questions:
- How many vertices, sides and angles does this figure have ? Name the figure.
- What is the point of intersection of two lines called ?
- What parameters do you identify in each figure ? (side, vertex, angle, plane surface and area )
- What can you say about the number of vertices and the number of sides in each figure ?
- Which figure would you think will be formed if the number of sides is increased indefinately.
- Evaluation:
- What determines the side or edge of the figure ?
- Are the students able to corelate the names with the number of sides ?
- Are the students able to appreciate the nature of shapes formed with each increasing side?
- Students can discuss angle sum property in each case by dividing the figure into triangles or quadrilaterals.
- Question Corner:
- A hexagon is a polygon with _________ angles.
- Is circle a polygon ?
- What is a polygon with 12 sides called ?
- You have a collection of sides from triangles and decagons. The total number of sides is 100 and you have 4 decagons. How many triangles do you have ?
Activity No #
- Estimated Time
- Materials/ Resources needed
- Prerequisites/Instructions, if any
- Multimedia resources
- Website interactives/ links/ / Geogebra Applets
- Process/ Developmental Questions
- Evaluation
- Question Corner
Concept #2. Characteristics of polygons
Learning objectives
Notes for teachers
Activity No #
- Estimated Time:
- Materials/ Resources needed:
- Prerequisites/Instructions, if any:
- Multimedia resources:
- Website interactives/ links/ / Geogebra Applets:
- Process/ Developmental Questions:
- Evaluation:
- Question Corner:
Activity No #
- Estimated Time
- Materials/ Resources needed
- Prerequisites/Instructions, if any
- Multimedia resources
- Website interactives/ links/ / Geogebra Applets
- Process/ Developmental Questions
- Evaluation
- Question Corner
Concept #3. Types of polygons
Learning objectives
- There are several ways to classify polygons. One way to classify them is by considering their angle measures and side length measures. If a polygon's angles and sides are equal, then the polygon is called a regular polygon. If the measures of a polygon's angles or side lengths differ, then the polygon is called an irregular polygon.
Notes for teachers
Activity No # Tangram
This activity has been taken from the website :http://www.cimt.plymouth.ac.uk/projects/mepres/allgcse/bs7act1.pdf
- Estimated Time : 40 minutes.
- Materials/ Resources needed: Chart papers, scissors, pencil, scale.
- Prerequisites/Instructions, if any
- The students should have understanding of basic shapes like square, rectangle, parallelogram, triangle and trapezium.
- They should be able to draw mentioned shapes accurately and cut exactly on boundaries.
- Multimedia resources
- Website interactives/ links/ / Geogebra Applets
- Process:
- This is a very old Chinese puzzle known as a tangram.
- Cut out the square below into 7 shapes.
- Cut out the 7 shapes and rearrange them to form:
(a) a square from two triangles, and then change it to a parallelogram; (b) a rectangle using three pieces, and then change it into a parallelogram; (c) a trapezium with three pieces; (d) a parallelogram with four pieces; (e) a trapezium from the square, parallelogram and the two small triangles; (f) a triangle with three pieces; (g) a rectangle with all seven pieces.
- Finally, put the pieces back together to form the original square.
- Developmental Questions:
- Were you all able to read and follow the instructions.
- Name and point the different shapes in the figure.
- Name the dimensions of each shape.
- Evaluation:
- Analyse how much space each shape is occupying.
- What can you refer to the space occupied by each shape.
- Question Corner:
- What are the characteristic properties of each shape: square, rectangle, triangle, parallelogram and trapezium ?
- What type of two triangles would you need to form a square ?
- What did you learn from this activity ?
Activity No #
- Estimated Time:
- Materials/ Resources needed:
- Prerequisites/Instructions, if any:
- Multimedia resources:
- Website interactives/ links/ / Geogebra Applets:
- Process/ Developmental Questions:
- Evaluation:
- Question Corner:
Activity No #
- Estimated Time
- Materials/ Resources needed
- Prerequisites/Instructions, if any
- Multimedia resources
- Website interactives/ links/ / Geogebra Applets
- Process/ Developmental Questions
- Evaluation
- Question Corner
Hints for difficult problems
Project Ideas
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