2-13-12

Triangles

BrainPop - Polygons:

Polygons BrainPop

Your Task:

• Using your cut-out triangles, sort your triangles into different groups.  
• You may sort by sides.  Think about the triangles and which ones have common attributes in terms of their sides.    
• Each group has to have a “rule” that the triangles ALL fit.
• List your observations and “rule” under the “attributes” column on your chart.
• Are there other “rules” that you can make within each group? If so, try to sort them again.

Share

• What were some rules that you came up with in each of the groups of triangles?
• What do we call triangles that fit these different rules?
• How do you think these classifications relate to other polygons?

Triangles are Classified by:

Angles

What are the types of angles?  

• __________
• __________
• __________

Characteristics of their sides

How can you describe the ways to classify by sides?

• __________
• __________
• __________

BrainPop - Triangles

Triangles - BrainPop

Color Coding & Naming:

Color the equilateral triangles yellow.

• What makes a triangle equilateral?

Color the isosceles triangles purple.

• What makes a triangle isosceles?  

Color the scalene triangles red.

• What makes a triangle scalene?

Naming triangles by characteristics of their sides

Color Coding & Naming:

• Color the background of triangles with acute angles blue.
• Color the background of triangles with right angles orange.  
• Color the background of triangles with obtuse angles green.

Naming triangles by characteristics of their angles

Reflection

In your journal, explain how a triangle can be described as an obtuse isosceles triangle. What are some of the possible measures of its' angles?  Draw the triangle and label the angles. 

BrainPop - Pythagoras:

Pythagoras - BrainPop

Reflect in Journal

• Pythagoras is a famous mathematician known for his work with triangles. Decide if an equilateral triangle can also be classified as an isosceles triangle (and vice versa).
• Persuade Pythagoras on why your reasoning is correct.
•  

Monday, February 12

• What are the various ways we can describe triangles?
• What were some types of triangles we classified yesterday (Friday)?
• Compare and contrast these triangles.

Organize

• Make a Tree Map of the different types of angles we discussed yesterday.
• Include a picture and description of each type.

How Else Can Triangles be Classified?

• We know that we can classify triangles based on the length of their sides.
• Was there another way that you could separate your triangles into sub-groups? (or smaller groups within your group.)

Classifying Triangles by Angles

• Right Triangle:
• A triangle with __________ right angle(s)
• Why can the triangle not have more right angles?
• Obtuse Triangle:
• A triangle with __________ obtuse angle(s)
• Why can the triangle not have more obtuse angles?

Classifying Triangles by Angles

• Acute Triangle:
• A triangle with _________ acute angle(s)

Angles in Triangles

• How many degrees make up a triangle?
• Use your protractor to measure the total angle degrees.

Reflect

• Decide if an equilateral triangle can be an obtuse or a right triangle.
• Back up your explanation with pictures, words, or both.