If the vertices if a square are joined in every possible way with straight lines, then 8 triangles and formed.
Four small triangles and four larger ones.
Can you find the 8 triangles?
How many triangles are formed when you join the vertices of a Regular Pentagon in every way?
Make sure you get all of them some small some large and some in between
What about a Regular Hexagon?
Can you see a pattern between the number of sides and the number of triangles?
Making a table/chart sometimes helps to see patterns
|
Name of Shape |
Number of Sides |
Number of Triangles |
|
Square |
4 |
8 |
|
Pentagon |
5 |
|
|
Hexagon |
6 |
|
|
|
|
|
|
Octagon |
8 |
|
Explain your pattern in words.
Can you predict the number of triangles for a Decagon(10-sided) Icosagon(20-sided)?
Now explore the number of triangles for irregular polygons
This activity adapted from "Points of Departure" Association of Teachers of Mathematics 1989.
No comments:
Post a Comment