Lesson Plan
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Inscribed Angles

For Teachers 9th - 10th
Students calculate the inscribed angle of a triangle. In this geometry lesson, students identify the angle created by intersection of a triangle and a circle. They see the relationship between the arc and the angle.
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Isosceles Triangles

For Teachers K - 2nd
Pupils investigate triangles. In this shapes geometry lesson, students define and state the attributes for equilateral, scalene, and isosceles triangles. Pupils locate the prefix "tri" in a variety of words and make connections with the...
Lesson Plan
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Types of Triangles

For Teachers 5th
Fifth graders explore the required functions of the Geometer's Sketchpad. Using the computer software, they construct similar triangles and identify them by angles and sides. Students classify triangles. Afterward, they complete problems...
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Equilateral Triangles

For Teachers 4th - 5th
Students examine the attribute of equilateral triangles. In this equilateral triangle lesson, students examine a number of paper triangles to determine how they are classified. They determine how triangles are depicted in Navajo rugs.
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Properties of Triangles

For Teachers 4th - 8th
Learners explore the relationship between how big a side of a triangle is and how big its opposite angle is by creating triangles using an interactive website.
Worksheet
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Easy Worksheet: Types of Triangles

For Students 9th - 12th
In this types of triangles worksheet, students solve 6 short answer problems. Students identify the type of triangle being described according to side length or angle measure.
Lesson Plan
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Exterior and Interior Angles of Triangles

For Teachers 10th
Tenth graders explore the exterior and interior angles of triangles. They use a theorem in order to prove a theorem about all polygons. Students use the theorem and its applications to find the angles of different types of triangles.
Worksheet
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Leveled Problem Solving Triangles

For Students 4th - 6th
In this triangles practice activity, students sharpen their problem solving skills as they solve 6 story problems.
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Concurrent Lines in Triangles

For Teachers 9th - 12th
Learners explore the concept of concurrent lines in triangles. In this concurrent lines in triangles lesson, students work in groups to investigate properties of concurrent lines in acute, right, and obtuse triangles. Learners use a...
Worksheet
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Parts of Similar Triangles

For Students 10th
In this parts of similar triangles learning exercise, 10th graders solve and complete 15 different statements related to naming the parts found in similar triangles. First, they identify each definition stated that describes an everyday...
Lesson Plan
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Exploring Angle/Pair Relationships

For Teachers 7th - 10th
Students find missing angles and sides of triangles. In this geometry lesson plan, students create intersecting lines to measure angles. They use Cabri Software to create virtual angles.
Lesson Plan
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8th Grade Math Classifying Triangles and Quadrilaterals

For Teachers 8th
Eighth graders engage in a lesson that is about classifying polygons with the focus being upon specific triangles and quadrilaterals. They conduct activities using cutouts for kinesthetic learners to help make connections while...
Worksheet
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Trigonometry Ratios in Right Triangles

For Students 10th
In this trigonometry ratios in right triangles worksheet, 10th graders solve 10 different trigonometric ratios that apply to right triangles. First, they define a trigonometric ratio and its three most common ratios, sine, cosine, and...
Worksheet
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Lines and Angles

For Students 6th - 8th
In this lines and angles worksheet, students identify parallel and perpendicular lines. They demonstrate the characteristics of a straight line. They determine missing angle measurements. This two-page worksheet contains 3 multi-step...
Worksheet
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Interior and Exterior Angles

For Students 10th
In this interior and exterior angles worksheet, 10th graders solve 10 different problems that include determining the interior and exterior of various triangles. They determine the measure of an exterior angle and then they determining...
Worksheet
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Year 10 Mathematics Triangle Test

For Students 11th - Higher Ed
In this math worksheet, students find the solutions to the missing angles and sides of the triangles using the correct trigonometric ratios.
Worksheet
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Congruent Triangles

For Students 10th
In this congruent triangles worksheet, 10th graders solve and complete 10 different problems that involve various congruent triangles. First, they determine the length of the third side given the other two. Then, students determine the...
Lesson Plan
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Congruent Triangles Postulates

For Teachers 3rd - 4th
Students discover three lettered postulates that prove triangles congruent.
Worksheet
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Lines and Angles

For Students 6th - 8th
In this math worksheet, students find the information concerning the line segments and angles. They define the complimentary and supplementary angles.
Lesson Plan
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Proving Triangles Congruent

For Teachers 10th - 12th
Students examine Triangle Congruency. In this measurement comparison lesson, students use inductive, deductive and analytical thinking skills to prove triangle congruency. Students analyze and record their findings on activity worksheets.
Worksheet
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Mid-Segment of a Triangle

For Students 10th - 11th
In this triangle worksheet, students examine triangle diagrams. They determine the perimeter, length of a line, midpoint of a line, and angle measurement from given information. This one-page worksheet contains ten problems.
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Triangles in Architecture

For Teachers 10th - 12th
Students find triangles in the real world. In this geometry lesson plan, students analyze and identify properties of two and three-dimensional objects. They differentiate between similarity and congruence.
Worksheet
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Parts of Similar Triangles

For Students 10th
In this parts of similar triangles worksheet, 10th graders solve 6 different problems related to determining the value of various parts of similar triangles. First, they find the value of x in the 2 figures shown. Then, students find the...
Lesson Plan
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Special Right Triangles

For Teachers 7th - 9th
Students identify the different parts of a right triangle. In this geometry lesson, students use the Pythagorean Theorem to identify missing sides and angles of a right triangle. They work with irrational and rational roots.