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Investigating Segments in a Triangle

For Teachers 9th - 12th Standards
Pupils investigate segments in a triangle by constructing a triangle using Cabri Jr. They construct segments within the triangle that lie on the midpoints of the triangle's sides. Learners then compare the slope of base of the triangle...
Lesson Plan
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Measuring Angles in a Triangle

For Teachers 9th - 12th Standards
High schoolers investigate the sum of the measures of the angles of a triangle. They draw a triangle and measure the interior angles. Using Cabri Jr., learners find the sum of the measures of the interior angles. The activity provides an...
Lesson Plan
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Nested Similar Triangles

For Teachers 9th - 12th Standards
Nested triangles have been created so that they share a common vertex and vertex angle. Learners drag the endpoints of the side that is opposite the common angle to discover the conditions that make the nested triangles similar. When...
Lesson Plan
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Area Measures and Right Triangles

For Teachers 9th - 12th Standards
Your class will investigate the relationship among different triangles. This geometry lesson, demonstrates how to make a connection between triangles and the Pythagorean Theorem. They identify the missing side or angle of a triangle.
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Trigonometric Functions of Acute Right Triangles

For Teachers 9th - 11th
Students derive the six trigonometric functions. In this trigonometry instructional activity, students show their understanding of trigonometric functions as they relate the right triangles. They find the missing angles and side use trig...
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Circumscribing a Circle About a Triangle

For Teachers 9th - 12th Standards
Pupils circumscribe a circle about a triangle. They construct a triangle using Cabri Jr and then circumscribe it. They then use knowledge of perpendicular bisectors and circumcenters to locate the center of the circle and then...
Lesson Plan
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Exploring the Circumcenter of a Triangle

For Teachers 9th - 12th Standards
Students construct the circumcenter of a triangle. For this constructing the circumcenter of a triangle lesson, students construct a triangle using Cabri Jr. Students draw perpendicular bisectors of the sides of the triangle. Students...
Lesson Plan
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Investigating Segments in a Right Triangle

For Teachers 9th - 12th Standards
High schoolers explore the concept of right triangles as they construct a right triangle using Cabri Jr. Learners find the midpoint of the hypotenuse and construct a line from the midpoint to the vertex of the right angle. They then...
Lesson Plan
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Ratios in Right Triangles

For Teachers 9th - 12th Standards
Learners calculate the sides of right triangles in this trigonometric ratios lesson. They use Cabri Jr. software and TI-83 or TI-84 calculators to find the side lengths and their ratios to each other for various triangles. The provided...
Lesson Plan
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Similar Triangles and Proportions

For Teachers 9th - 12th Standards
Pupils investigate similar triangles and proportions as they make conjectures about the length of sides of similar triangles. For this lesson, have your class construct similar triangles using Cabri Jr so that they share a common vertex.
Lesson Plan
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Triangle Inequality Theorem

For Teachers 9th - 12th Standards
High schoolers investigate the relationship between angle measures and sides of a triangle and the relationships among the three sides of a triangle. The use of technology (Cabri, Jr.) allows learners to make and test conjectures as they...
Worksheet
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Find the Perimeter of Triangles

For Students 5th - 7th
In this perimeter worksheet, students calculate the perimeter of various different triangles. There are four problems to solve.
Lesson Plan
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Exploring the Orthocenter of a Triangle

For Teachers 9th - 12th Standards
Young mathematicians explore the concept of triangles as they construct altitudes of triangles to find the orthocenter. Learners construct their triangles using Cabri Jr. on their graphing calculators and find that the altitudes of a...
Worksheet
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Find the Side of the Triangle

For Students 9th - 10th
For this geometry worksheet, students investigate the missing side of  triangles given the other two sides. There are 5 questions with a solution key.
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Midsegments of a Triangle

For Teachers 9th - 12th Standards
Students analyze midsegments of triangles in this instructional activity. They use Cabri Jr. software to observe the relationships between interior angles and midsegments of triangles. Specific instructions for creating this...
Lesson Plan
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Triangle Sum Theorem

For Teachers 9th - 12th Standards
Teach your class how to solve problems using the triangle sum theorem. In this geometry instructional activity, students identify the missing angles in a triangle using the sum theorem. They graph triangles on the TI and moves the sides...
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Triangle Midsegment

For Teachers 9th - 12th Standards
Learn how to calculate the length and midsegments of triangles. Students differentiate between similar and congruent triangles. They create a spreadsheet with their findings.
Lesson Plan
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30-60-90 Right Triangles in Cabri Jr.

For Teachers 9th - 12th Standards
Young mathematicians draw and label right triangles using Cabri Jr. technology. They create other special right triangles and identify the length of the hypotenuse and each leg. Young scholars explore the ratios to determine how the...
Lesson Plan
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Exploring Characteristics of Triangles

For Teachers 9th - 11th
Students draw triangles and explore the classification of each using the measures of interior angles and lengths of sides. They investigate the sum of the interior angles of various triangles and conjecture and prove the theorem: The...
Worksheet
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Classifying Triangles

For Students 6th
In this classifying triangles worksheet, 6th graders write the type of triangle, acute, right or obtuse, for 9 pictures of triangles, answers included.
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A Triangle Expansion

For Teachers 9th - 12th
Students review the foil method used to multiply two binomials. In this lesson on evaluating algebraic expressions, students are able to identify the coefficient in an algebraic expression, "act out" the foil method of multiplying...
Activity
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Triangle Series

For Teachers 9th - 12th Standards
Your algebra learners emphasize the"geometric" in geometric series as they use a common ratio between algebraic terms and find that it corresponds to a repeated similarity transformation. 
Lesson Plan
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Circumcenter of a Triangle

For Teachers 9th - 12th Standards
Your geometry learners will discover and show the construction of the circumcenter of a triangle. Guided by the steps in the activity, they construct perpendicular bisectors of each side that have a point of concurrency called the...
Lesson Plan
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When Does SSA Work to Determine Triangle Congruence?

For Teachers 9th - 10th Standards
Your learners will make good use of the Socratic method in a collaborative task that begins with an assumed solution and ends with deeper understanding of the idea of determining two triangles congruent.

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