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Anita Zuba- Triangle Classification, Mathematics, Grade: 9-12
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Standards StrategiesTechnologies
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4.2.12 A.
Geometric Properties		Teacher centered:The lesson plan only uses an online activity sheet, which does not support the lesson. Using the online activity sheet, will not benefit the students in any way.
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3. Apply the properties of geometric shapes.To begin the class, teacher asks students the following questions:

-How can you classify triangles according to their angles? [right, acute, obtuse]
-How can you classify triangles according to their sides? [equilateral, isosceles, scalene]		I used the Geometer's Sketchpad for this lesson, which supports the concept directly and allows the students to investigate different triangles. Not only will it help students visualize the properties of triangles, but also makes the lesson more interesting and fun. The lesson also becomes more meaningful, by using this technology.
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4. Establish the validity of geometric conjectures using deduction, prove theorems, and critique arguments made by others.After the introduction, the teachers places an overhead copy of the activity sheet on the projector. Reads the directions aloud to students, and then asks students to suggest a point C that would create a right triangle.
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4.5 F TechnologyTo accompany this discussion, teacher uses the Triangle Classification online activity for demonstration purposes.
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Use technology to analyze mathematical information.
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Student Centered:
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NET-S StandardsTeacher calls on a volunteer to come to the overhead projector and, without any explanation, place a dot on the transparency. Then, allows the class to discuss. Would the point form a right triangle? How do you know?
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1d. Creativity and Innovation- Identify trends and forecast possibilities During this discussion, teacher asks questions to prompt and further student thinking.
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6a. Technology Operations and Concepts- Understand and use technology systemsStudents work alone on an activity sheet. When finished, discuss with partner. After which, the whole class discusses the students' discoveries.
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Instead of the online activity sheet, I would use the Geometer's Sketchpad to demonstrate different triangles. Students would be able to create different triangles, measure the sides and angles, and classify them according to the properties.
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This lesson was prepared by Samuel E. Zordak, based on an idea suggested by Jim Rubillo. http://illuminations.nctm.org/LessonDetail.aspx?id=L656
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