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Worksheet
Curated OER

Area of Right-Angled Triangles

For Teachers 3rd - 5th Standards
There's a trick to solving the area of a triangle, and it involves a skill your geometers have already mastered. Help them discover the connection between finding a rectangle's area and finding a right triangle's area as they solve for...
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Lesson Plan
Curated OER

Getting It Right! An Investigation of the Pythagorean Theorem

For Teachers 6th - 8th
Learners construct a variety of right triangles using a right-angled set square, cutting corners from pieces of paper or cardboard, and using dynamic geometry software. They measure the sides of these various right triangles and record...
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Lesson Plan
Curated OER

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...
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PPT
Curated OER

Classifying Triangles

For Teachers 5th - 7th
This presentation shows how triangles are classified by angle measurement and length of sides.  It reviews isosceles, scalene, obtuse, right, and acute classifications and includes questions for students to classify some of the triangles...
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Lesson Plan
Curated OER

Getting It Right!

For Teachers 6th - 8th
Students construct right triangles, measuring the sides and recording the measurements in spreadsheets. They analyze their measurements for patterns and research the Internet for information on Pythagoras.
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Assessment
Mathed Up!

Angles

For Students 6th - 8th Standards
What does a geometric farmer drive? A protractor, of course! A set of assessment worksheets prompts learners to use a protractor as they measure angles, name angles, and identify lines. Use the video as a way to introduce the concepts. 
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Lesson Plan
West Contra Costa Unified School District

Pythagorean Theorem and Its Converse

For Teachers 9th - 12th Standards
Challenge scholars to prove the Pythagorean Theorem geometrically by using a cut-and-paste activity. They then must solve for the missing sides of right triangles.
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Worksheet
Curated OER

Solving Problems with Angles

For Students 4th - 6th
Upper elementary math whizzes complete word problems having to do with measurements of angles. They complete 10 multiple choice problems.
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Lesson Plan
Curated OER

Triangle Classificaition with Geometer's Sketchpad.

For Teachers 7th - 12th
Students 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
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University of Adeaide

Basic Trigonometry and Radians

For Teachers 9th - 12th Standards
A fabulous set of examples and problems that introduce basic trigonometry concepts, this packet is set apart by the care it takes to integrate both radians and degrees into the material. After defining radians, the author demonstrates...
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Assessment
Bowland

Rods and Triangles

For Teachers 6th - 9th
Scholars explore triangles with rods of different lengths. Using rods of 2, 4, 6, 8, and 10 cm class members build as many different types of triangles as they can. They also describe properties of these triangles and determine...
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Worksheet
Curated OER

Countdown Challenge: Geometry Exploration

For Students 6th - 8th
In this geometry worksheet, students identify and draw right angles, acute angles, obtuse angles and straight angles. This one-page worksheet contains 34 problems.
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Lesson Plan
Curated OER

Using Trigonometry

For Teachers 5th
Fifth graders explore the use of trigonometry to find unknown sides and angles in right-angled triangles, taking the concepts that were developed in the previous unit and looking at different ways of practicing the new skills. Students...
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Lesson Plan
Curated OER

Investigating the Idea of Tan

For Teachers 5th
Fifth graders use tan to solve problems involving right-angled triangles. They solve equations of the form tan(8) =a, for a between 180 degrees and 360 degrees. They state the value of tan (8) in special cases.
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Assessment11:36
Mathed Up!

Area of Compound Shapes

For Students 7th - 10th Standards
Scholars learn how to determine the area of compound shapes by finding the areas of the basic shapes that make it up. Pupils find the areas by adding areas together or subtracting them.
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Lesson Plan
Curated OER

Dizzy Heights

For Teachers 5th
Fifth graders explore ways to measure the height of an inaccessible object. They measure lengths using a tape measure or ruler. Students measure angles using a protractor and estimate heights.
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Worksheet
Curated OER

Unit 9 Trigonometry

For Students 9th - 11th
In this trigonometry worksheet, students find the lengths of triangles. They construct triangles and spirals. Students complete indirect measurement problems. They find the distance between objects and determine the volume of rectangular...
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Lesson Plan
Curated OER

Introducing Trig

For Teachers 5th
Fifth graders explore the importance of triangles in the real world. They find the unknown side of a right triangle using a scale drawing. Students use Pythagoras' Theorem and other appropriate ratios.
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Worksheet
Curated OER

Cosine

For Students 10th - 12th
In this cosine worksheet, students find the cosine of x for different measurements of triangles. Students complete 10 cosine problems.
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Lesson Plan
Curated OER

Measuring Angles

For Teachers 3rd
Third graders describe an amount of turn from a particular position to another using the 'circular' benchmarks of 0, ++, ++, ++, and full turn. Estimation language such as 'just about', 'between', 'not quite', 'just over', and similar...
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Interactive
Curated OER

Ten Multiple Choice Length Problems

For Students 9th - 10th
In this distance worksheet, students calculate the lengths of sides and diagonals of figures.  Students also compute lengths in shadow problems.  The solutions are provided by clicking on the "show answers" tab at the bottom of the page.
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Lesson Plan
Curated OER

Trigonometry

For Teachers 8th
Eighth graders practice calculating the unknown length of a right angle triangle. They also examine the pythogoram theory in groups. They help each other work through the problems.
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Lesson Plan
Curated OER

II Similar

For Teachers 8th - 10th
Students, through lecture and guided practice, discover the properties of similar triangles. They use given measurements of one triangle to find a missing measurement of a similar triangle. They apply this knowledge in real-life...
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Lesson Plan
Curated OER

Triangles

For Teachers 3rd - 5th
This unit enables scholars to apply the rule for area of a triangle (area equals half base times height). They practice multiplication and division strategies as they calculate areas.