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Lesson Plan
Curated OER

Solve Right Triangle

For Teachers 9th - 11th
In this trigonometric applications worksheet, learners solve for the missing side of a right triangle using a trigonometric ratio. There are 46 questions, 10 of which are word problems.
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Lesson Plan
Curated OER

Special Segments in a Triangle

For Teachers 10th
In this geometry worksheet, 10th graders review the vocabulary associated with the special segments of a triangle and the associated points of concurrency and solve problems in which they find the indicated missing angle or...
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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 lesson, students work in groups to find the stated measurements of triangles, quadrilaterals, pentagons and hexagons. Students...
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Lesson Plan
Curated OER

Isosceles Triangles

For Teachers 9th - 10th
Students identify the properties of an isosceles triangle. In this geometry activity, students find the midpoint, median and angle bisector of a triangle. They construct angle bisectors and measure missing angles.
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Lesson Plan
Curated OER

Angles and Triangles

For Teachers 8th
Eighth graders examine Jewish symbols. In this Holocaust lesson, 8th graders discuss the meanings behind the Swastika and the Star of David. Students also measure the angles and shapes with the symbols.
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Worksheet
Curated OER

Measuring Angles with a Protractor

For Students 7th - 8th
In this measuring angles worksheet, students solve and complete 3 various types of problems. First, they complete each statement by measuring each angle shown. Then, students measure all three angles in a triangle and add them.
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Lesson Plan
EngageNY

Incredibly Useful Ratios

For Students 9th - 10th Standards
Start the exploration of trigonometry off right! Pupils build on their understanding of similarity in this lesson that introduces the three trigonometric ratios. They first learn to identify opposite and adjacent...
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Lesson Plan
EngageNY

The Definition of Sine, Cosine, and Tangent

For Students 9th - 10th Standards
Introduce your classes to a new world of mathematics. Pupils learn to call trigonometric ratios by their given names: sine, cosine, and tangent. They find ratios and use known ratios to discover missing sides of similar...
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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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Lesson Plan
Illustrative Mathematics

Two Wheels and a Belt

For Teachers 9th - 10th Standards
Geometry gets an engineering treatment in an exercise involving a belt wrapped around two wheels of different dimensions. Along with the wheels, this belt problem connects concepts of right triangles, tangent lines, arc length, and...
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Lesson Plan
EngageNY

Prove the Pythagorean Theorem Using Similarity

For Students 9th - 10th Standards
Amaze your classes with the ability to find side lengths of triangles immediately — they'll all want to know your trick! Learners use the Pythagorean Theorem and special right triangle relationships to find missing side lengths.
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Activity
101 Questions

Marine Ramp

For Students 9th - 12th Standards
Boat ramps move with waves and changes in water level. Scholars decide on the proper length for a ramp so the angle connecting both sides is appropriate. They visualize the situation and use a simulation to view the results with their...
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Worksheet
Curated OER

Triangles

For Students 10th
In this triangles worksheet, 10th graders solve 12 different problems that include various angles of triangles. First, they determine the measure of an exterior angle. Then, students determine the measure of any of the base angles of an...
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Worksheet
Math Mammoth

Calculating Angles in a Triangle 2

For Students 5th - 6th
In this geometry worksheet, learners calculate unknown angles in diagrams of 3 triangles. They draw and answer short answer questions about angles. They then calculate the designated angles in 2 more diagrams.
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Worksheet
Curated OER

Interior and Exterior Angles of Polygons

For Students 10th
For this angles of polygons worksheet, 10th graders solve and complete 18 different problems that include determining various interior and exterior angles. First, they determine the measure of various angles described in the first half...
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Worksheet
Curated OER

Properties of Angles, Lines, and Triangles

For Students 10th
In this properties of angles, lines and triangles worksheet, 10th graders solve and complete 28 different problems that include determining the measurement of various figures shown. First, they use the geometric properties and theorems...
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Lesson Plan
Curated OER

Geometry Regents Questions: Isosceles Triangle Theorem

For Teachers 9th - 12th
In this isosceles triangle worksheet, students solve 19 multiple choice and short answer problems.  Students use the isosceles triangle theorem to determine unknown angle measures.
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Worksheet
Curated OER

Triangle Similarity

For Students 10th
In this triangle similarity activity, 10th graders solve and complete 12 different problems that include defining similar and 3 similar statements using only sides and angles. First, they determine if each pair of triangles shown are...
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Worksheet
Curated OER

Refraction Through a Triangle

For Students 9th - 12th
In this refraction through a triangle worksheet, high schoolers use a given diagram of light striking a triangular piece of plexiglass to determine the light ray's angle of incidence, the ray's angle of refraction, they use Snell's Law...
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Worksheet
Curated OER

Right Triangle Trigonometry: Finding Missing Sides and Angles

For Students 9th - 11th
In this right triangle trigonometry worksheet, students find the measure of specified angles. Students determine the length of the missing side of a right triangle. This four-page worksheet contains 24 problems. Answers to the worksheet...
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Worksheet
Curated OER

Tricky Triangle

For Students 9th - 12th
In this triangle worksheet, students solve 1 word problem about the lengths of a triangle. Students determine the length of the longest side given the ratio of the angle measures.
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Worksheet
Curated OER

Triangles

For Students 10th
For this triangles worksheet, 10th graders solve and complete 22 different problems related to various types of triangles. First, they name the shortest and longest sides and the smallest and largest angles in each of triangles...
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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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Lesson Plan
Curated OER

The Truth About Triangles And Proofs

For Teachers 9th - 12th
High schoolers engage in a lesson that is about the classification of triangles and the mathematical proofs involved in working with them. They work on a variety of problems that are created by the teacher with the focus upon the...