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Lesson Plan
Curated OER

Interior/Exterior Polygon Angles and Tessellations

For Teachers 9th - 11th
Students discover the sum of the interior and exterior angles of several polygons. In this Geometers sketchpad instructional activity, students work in groups to find the stated measurements of triangles, quadrilaterals, pentagons and...
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Lesson Plan
Curated OER

Triangle Classificaition with Geometer's Sketchpad.

For Teachers 7th - 12th
Learners use Geometer's Sketchpad to draw triangles and explore the classificaiton of each using the mearsures of interior angles and the lengths of the sides.
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Worksheet
Math Mammoth

Construct Line Segments and Angles

For Students 6th - 7th
In this math worksheet, learners are asked to used a compass and straight edge to construct copies of shapes, angles and line segments.
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Lesson Plan
Curated OER

The Sum of All Angles

For Teachers 7th - 10th
Young scholars add up the different angles using the angle addition postulate. In this geometry instructional activity, students differentiate between interior and exterior angles. They calculate the different angles for triangles and...
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Worksheet
Curated OER

Congruence of Triangles

For Students 10th
In this congruence of triangles worksheet, 10th graders solve and complete 10 different problems that include measuring the congruence of various triangles. First, they determine the length of a third side of an isosceles triangle. Then,...
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Interactive
Curated OER

Try These Angles! Exploring Angles

For Students 5th - 8th
In this angles worksheet, students answer multiple choice questions about different types of angles in shapes. Students complete 10 questions.
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Lesson Plan
Curated OER

Patterns in the Sums of Polygon Angles

For Teachers 6th
Sixth graders discover the patterns of sums of polygon angles. In this math lesson plan, 6th graders study the properties of geometric shapes to solve problems as they participate in hands-on activities.
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Lesson Plan
EngageNY

Informal Proof of AA Criterion for Similarity

For Teachers 8th Standards
What does it take to show two triangles are similar? The 11th segment in a series of 16 introduces the AA Criterion for Similarity. A discussion provides an informal proof of the theorem. Exercises and problems require scholars to apply...
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Worksheet
Curated OER

Angles in Polygons

For Students 10th
In this geometry worksheet, 10th graders solve problems involving quadrilaterals using the angle sum of quadrilaterals. They solve for linear pairs, opposite angle theorem and triangular angles. There are 5 questions.
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Lesson Plan
Curated OER

Angles in Triangles

For Teachers 8th
Eighth graders translate word problems using mathematical ideas. In this geometry lesson, 8th graders identify angles of triangles using equations and the triangle sum theorem. They create angles with a protractor and straight edge.
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Worksheet
Curated OER

Triangle Fundamentals

For Students 8th - 12th
In this geometry worksheet, students observe a triangle marked with three angles and are given two measures to find the missing third measure. A second diagram is given with six angles. There are 20 questions.
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Handout
El Paso Community College

Geometry Definitions

For Students 7th - 9th Standards
Geometry is full of shapes, figures, and corresponding things here and there. The guide shares all of the key pieces of geometric information in a nicely color-coded and labeled sheet. 
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Interactive
Curated OER

Try These Angles! Exploring Angles: Post Test

For Students 5th - 8th
In this angles worksheet, students answer multiple choice questions about angles on their own and angles inside shapes. Students complete 10 multiple choice questions.
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Worksheet
Curated OER

Triangle worksheets

For Students 10th
In this geometry worksheet, 10th graders explore triangle properties, including the sum of the measures of the angles of a triangle, the triangle inequalities, properties of isosceles triangles, properties of congruent triangles, and...
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Worksheet
Curated OER

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...
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Lesson Plan
Beacon Learning Center

Angles and Algebra

For Teachers 6th - 8th
Middle schoolers calculate angle measure for triangles and complementary/supplementary angles. After a lecture/demo, students utilize a worksheet imbedded in this plan to gain practice.
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Lesson Plan
Curated OER

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.
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Worksheet
Curated OER

Polygons

For Students 6th - 10th
In this polygons worksheet, students read about and complete many activities involving triangles, angles, and symmetry. Students complete 17 pages of activities.
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Lesson Plan
Key Curriculum Press

Triangle Inequalities

For Teachers 8th - 11th Standards
Properties about triangles are explored in this instructional activity. Geometers make conjectures about the length of a triangle's sides, the length of the angles in relation to the length of the sides, and the measure of the exterior...
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Lesson Plan
Curated OER

Triangle Inequality Theorem

For Teachers 8th - 10th
Students use the inequality theorem to solve triangles and their properties. In this geometry instructional activity, students are given spaghetti of different lengths and asked to create triangles. They conclude the necessary length...
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Unit Plan
Mathematics Vision Project

Geometric Figures

For Teachers 10th - 12th Standards
Logical thinking is at the forefront of this jam-packed lesson, with young mathematicians not only investigating geometric concepts but also how they "know what they know". Through each activity and worksheet, learners wrestle with...
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Lesson Plan
Curated OER

Applying Special Right Triangles

For Teachers 10th
In this geometry worksheet, 10th graders use the theorems regarding right triangles to find the missing length in a special right triangle. The one page worksheet contains eleven questions. Answers are included.
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Lesson Plan
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Curated OER

A Rectangle in the Coordinate Plane

For Teachers 7th - 9th Standards
A quadrilateral is drawn on the coordinate plane, and eighth grade geometers find the length of each side and the diagonals by applying the Pythagorean theorem. 
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Lesson Plan
Curated OER

Triangle Exterior Angles Theorem

For Teachers 7th - 9th
Students identify the measure of missing exterior angles. In this geometry lesson,students define and apply the exterior angle theorem to solve problems. They use Cabri software to create different angles and make investigations.