Something for young mathematicians to remember: the sum of any two sides must be greater than the third. Class members investigates the Triangle Inequality Theorem to find the relationship between the sides of a triangle. At the same time, they collect data to develop the relationship between the sizes of the angles of a triangle and the lengths of its sides.

Concepts

triangle properties, triangles inequalities, acute triangles, equilateral triangles, obtuse triangles, isosceles triangles, scalene triangles, triangles

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Additional Tags

math

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Instructional Ideas

• Use geometry software to create triangles that can be manipulated to find the range of possible lengths of a third side

Classroom Considerations

• Class members should know the sum of the angles of a triangle is 180
• Requires the use of pipe cleaners or narrow strips of paper that are a foot in length

Pros

• Contains a variety of assessment questions and tasks
• Includes strategies for differentiation

Cons

• None

Common Core

7.G.A.2 HSG-CO.C.10 MP6 MP8