Determine if three side lengths will create a unique triangle or no triangle.
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The following materials are needed for this lesson: AngLegs or wooden skewers (see the blog post Triangle Inequality Skewers by Elissa Miller), compasses, rulers.
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Using AngLegs or wooden skewers, investigate different side lengths that will create a triangle.
Complete the chart below, adding rows as needed.
Side length $$a$$  Side length $$b$$  Side length $$c$$  Triangle? If not, explain why 
What conclusion can you make about the side lengths of a triangle?
In each diagram below, line segment $${AB}$$ is 4 units. Two circles are drawn with a given radius and center at point $$A$$ and point $$B$$.
Diagram 1: Circle with center $$A$$ has a radius of 4 units. Circle with center $$B$$ has a radius of 2 units. 
Diagram 2: Circle with center $$A$$ has a radius of 1 unit. Circle with center $$B$$ has a radius of 2 units.

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The following resources include problems and activities aligned to the objective of the lesson that can be used to create your own problem set.
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Which of the following set of side lengths could not be used to create a triangle?
A triangle has two side lengths that measure 6 in. and 9 in. Which of the following could be the measure of the third side? Select all that apply.
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