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Lesson Plan
EngageNY

An Area Formula for Triangles

For Teachers 11th - 12th Standards
Use a triangle area formula that works when the height is unknown. The eighth installment in a 16-part series on trigonometry revisits the trigonometric triangle area formula that previously was shown to work with the acute triangles....
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Lesson Plan
Alabama Learning Exchange

What You Know About the Bermuda Triangle?

For Teachers 9th - 12th Standards
Get lost in the classifications. Using the backdrop of the Bermuda Triangle, pupils classify it by angle and side measures. They also learn information about the triangle and its history.
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Lesson Plan
Curated OER

Geometry of Triangles - Week 6

For Teachers 10th - 12th
In this triangle worksheet, learners explore the characteristics of triangles. They find the area of a pentagon, lengths of the sides of a triangle and the area of a quadrilateral. This two-page worksheet contains seven problems.
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Lesson Plan
Curated OER

Special Segments of Triangles Jigsaw Activity

For Teachers 11th - 12th
Students identify the special segments of triangles, the median, angle bisector, altitude, and perpendicular bisectors.
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Lesson Plan
Curated OER

Travel Triangles

For Teachers 8th - 11th
Students demonstrate and understanding of the three types of angles using triangles and quadrilaterals. In this angles lesson plan, students learn about acute, obtuse and right angles. They use cut-outs to find the areas of triangles and...
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Worksheet
Curated OER

Area and Periemeter

For Students 10th
For this geometry worksheet, 10th graders determine the area and perimeters of various quadrilaterals and triangles.  The one page worksheet contains ten problems.  Answers are not provided. 
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Lesson Plan
Curated OER

Geometry of Triangles - Week 6

For Teachers 12th - Higher Ed
In this geometry of triangles worksheet, learners find the length of sides, are, and angle measurement of inscribed triangles, pentagons, and midpoint of a line. This two-page worksheet contains seven problems.
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Lesson Plan
Curated OER

Review of Triangles

For Teachers 8th - 10th
Students investigate the Pythagorean Theorem. In this geometry lesson, students define angles and sides of right triangles. They calculate the area and surface area using formulas derived by the Pythagorean Theorem.
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Worksheet
Curated OER

Geometry Course Review

For Students 10th
In this geometry review set of worksheet, 10th graders solve and complete 139 various types of problems. First, they find the slope-intercept form of a line passing through a point and parallel to a line given. Then, students find the...
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Lesson Plan
Curated OER

Pythagorean Theorem: Triangles and Their Sides

For Teachers 8th - 10th
Students investigate triangles and their relationship to each other. In this geometry lesson, students solve right triangles using the properties of the Pythagorean Theorem. They differentiate between right, acute, straight and oblique...
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Lesson Plan
Curated OER

Twenty-Five Measures of the Angles of a Triangle Problems

For Teachers 9th - 10th
In this triangle worksheet, students calculate the measures of the angles or the sums of the measures of the angles in twenty-five triangle problems and hands-on activities.  The solutions are provided.
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Lesson Plan
Virginia Department of Education

The Pythagorean Relationship

For Teachers 9th - 11th Standards
Add up areas of squares to discover the pythagorean relationship. Small groups create right triangles with squares along each side. They calculate the areas of each square and notice the relationship. Groups construct other types of...
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Worksheet
Curated OER

Tessellations

For Students 10th
In this tessellations worksheet, 10th graders solve 6 different types of tessellation problems that includes drawing. First, they define polygon, regular polygon, tessellation, regular tessellation, and semi-regular tessellation. Then,...
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Assessment
EngageNY

End-of-Module Assessment Task: Pre-Calculus Module 4

For Students 11th - 12th Standards
Challenge your scholars to show what they know about the Law of Sines, Law of Cosines, and inverses. The six-question assessment is the last in a series of 16. Pupils find the area of triangles and show that the Law of Sines and Law of...
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Lesson Plan
Curated OER

Exploring Special Segments in Triangles

For Teachers 9th - 12th
Students discover that four special segments have a common intersection point. They identify the position of the intersection point in triangles. They produce conjectures about areas of the divided triangles.
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Lesson Plan
Curated OER

Pythagorean Relationships

For Teachers 9th - 12th Standards
Oh that Pythagorean Theorem is so useful. Learners engage in a 45 minute learning activity that requires them to solve for missing angles and sides of a right triangle. They'll use the Pythagorean Theorem to find the rations of sides and...
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Activity
Shasta County Office of Education

Human Graphing Activity

For Teachers 5th - 9th Standards
Take graphing outside and make a giant coordinate plane to plot your human points. Young graphers are each given a coordinate for a particular shape and asked to make the geometrical shapes one by one. Those not plotted are to write down...
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Lesson Plan
Curated OER

The Centroid : Balancing the History

For Teachers 10th - 12th
Students discover the centroid of a triangle based on Euclid's constructions. They explore locus of points of a median. They understand properties of the segments that form the median and areas of the smaller sections formed by the median.
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Lesson Plan
Curated OER

Geometry w/o Figures - Week 7 (Basic Geometry Formulas)

For Teachers 10th - 12th
In this basic geometry worksheet, students use basic formulas of geometry to find the area of a polygons, the number of sides of a polygon, and sum of the angles of various polygons. This three-page worksheet contains eight problems.
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Lesson Plan
Curated OER

Pythagorean Theorem by Graphic Manipulation

For Teachers 7th - 9th
There are many different ways to show a proof of the Pythagorean Theorem.  Here is a nice hands-on paper cutting activity that shows a graphic representation. You can even challenge your young Pythagoreans to come up with their own...
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Worksheet
Curated OER

Geoboard Activity

For Students 10th
For this geometry worksheet, 10th graders use geoboards or the grid representation of a geoboard to construct the indicated geometric figure. The three page worksheet contains twenty-seven questions. Answers are not included.