Isosceles Theorem Worksheets

What is the Isosceles Theorem? Solving isosceles triangles requires special considerations since it has unique properties that are unlike other types of triangles. Therefore, when you’re trying to prove those triangles are congruent, you need to understand two theorems beforehand. These two isosceles theorems are the Base Angles Theorem and the Converse of the Base Angles Theorem. The base angles theorem suggests that if you have two sides of a triangle that are congruent, then the angles opposite to them are also congruent. On the other hand, the converse of the Base Angles Theorem showcase that if two angles of a triangle are congruent, then the sides opposite to them will also be congruent.

  • Basic Lesson

    Guides students through solving problems and using the Isosceles Theorem.

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  • Intermediate Lesson

    Demonstrates the concept of advanced skill while solving Isosceles Theorem based problems. In △ ABC, the vertices have the coordinates A(0,3), B(-2,0), C(0,2). Is this an isosceles triangle?

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  • Independent Practice 1

    A really great activity for allowing students to understand the concepts of the Isosceles Theorem. Example: The altitude to the base of an isosceles triangle does not bisect the vertex angle. ( True or False)

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  • Independent Practice 2

    Students use Isosceles Theorem in 20 assorted problems. The answers can be found below.

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  • Homework Worksheet

    Students are provided with 12 problems to achieve the concepts of Isosceles Theorem. The altitude to the base of an isosceles triangle does not bisect the base. (True or False)

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  • Skill Quiz

    This tests the students ability to understand Isosceles Theorem.

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  • Answer Key

    Answers for all lessons and independent practice.

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Grad School Joke

How many graduate students does it take to change a light bulb?

Only one. But it takes nine years.