Identifying Triangles

Unit 4C-Triangle Geometry

LT7: I can identify different types of triangles based on different measures.

Identifying

There are 3 different ways to identify triangles based on information given (angles and sides)

1.) A Unique Triangle

2.) More Than One Triangle3.) No Triangle

What Is A “Unique” Triangle?A unique triangle means there is ONLY ONE WAY to create the triangle.

All unique triangles are congruent (the same) even though you may have to “flip” or “turn” them to line up

Criteria For A Unique TriangleThere are certain criteria that must be met in order for a triangle to be considered a unique triangle…1.) SSS Triangles

2.) SAS triangles with an included angle3.) ASA triangles with an included side4.) ASA triangles with a nonincluded side

What Is “More Than One” Triangle?

There are certain criteria that must be met in order for more than one triangle to be made with the same given information…1.) SAS triangles with a nonincluded angle – EXCEPT if the given sides are the same length (isosceles) in which case you will get a unique triangle

2.) AAA Triangles

What Is “No” Triangle?

There are certain criteria that if you are given you will NOT be able to create a triangle…

1.) If the sum of all the angles in the triangle does NOT equal 180°

2.) If the sum of 2 of the sides of the triangle is NOT greater than the third side

Let’s Review

Now Let’s Practice

Example 2

Draw Triangle QRS where Angle R=40°, RQ=12cm, and RS=8cm. Is the triangle unique, more than one, or none?

Example 3

Example 4

Example 5

Example 6

Example 7

Any Questions???????

Your Turn! Complete the handout individually to

assess what you have now learned about creating a unique triangle, more than one triangle, or no triangle.

We will discuss your answers as a class once everyone is finished.