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Lesson Plan
Curated OER

Can a Geometric Mean be Nice?

For Teachers 11th - 12th
In this Geometry instructional (work)sheet, students are instructed on how to find the geometric mean.  Students are then shown how the geometric mean is applied to proving similar triangles.
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Lesson Plan
Curated OER

Pythagorean Theorem

For Teachers 7th - 9th
Students solve right triangles using the Pythagorean Theorem.  In this solving right triangles using the Pythagorean Theorem lesson, students find the missing side of a right triangle.  Students find the hypotenuse given two...
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Interactive
Noetic Learning

Kinds of Triangles (Online Interactive)

For Students 3rd - 4th
In this triangles learning exercise, students analyze pictures of four triangles. For each triangle, students mark if it is acute, obtuse, or right.
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Worksheet
Curated OER

Special Right Triangles

For Students 10th
In this right triangles worksheet, 10th graders solve and complete 16 various types of problems. First, they find the missing side lengths in each illustration shown. Then, students place the letter of each problem on the lines at the...
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Worksheet
Curated OER

Sine

For Students 10th
In this sine worksheet, 10th graders solve 10 different problems by determining the sine in each right triangle shown. They determine the sine of one point by applying the other points given in the problem.
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Worksheet
Curated OER

Geometry Puzzle

For Students 2nd - 3rd
In this geometry puzzle worksheet, students identify and complete a puzzle that includes 7 different geometrical shapes. They identify and name each shape listed at the bottom. Then, students label every shape in the puzzle with the...
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Lesson Plan
Curated OER

Investigating the Idea of Cos

For Teachers 5th
Fifth graders use cos to solve problems involving right-angled triangles. They solve equations of the form cos(++) = a, for a between -180 and 360 degrees. They state the value of cos(++) in special cases and graph y = cos(++).
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Lesson Plan
Curated OER

Area graphics for 7th graders

For Teachers 6th - 7th
Students randomly select dimensions for three geometric shapes (square, right triangle and circle). From the graphs they compare and contrast the graphical results of each shape.
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Lesson Plan
Curated OER

Calculating the shortest distance between two points

For Teachers 8th
Eighth graders find the length of the third side of a right triangle.
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Interactive
Government of Alberta

Learn Alberta: Math Interactives: Exploring Square Roots Video

For Students 6th - 8th Standards
This video illustrates the concepts of square roots, slope, and the Pythagorean Theorem as they are used in designing and constructing skate park rails, ramps, and pipes. An interactive activity is also included where students are able...
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Interactive
Government of Alberta

Learn Alberta: Math Interactives: Exploring Trig Ratios

For Students 6th - 8th
Investigate the cosine, sine, and tangent ratios of trigonometry using this interactive Learn Alberta math resource. Students will use these ratios to determine a right triangle's unknown side or angle. Be sure to follow the link to the...
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Lesson Plan
Oswego City School District

Regents Exam Prep Center: Special Right Triangles 45, 45, 90

For Teachers 9th - 10th
This Oswego City School District Regents Exam Prep tutorial shows two special formulas that are used to determined the measures of the legs of a 45-45-90 triangles. If you can't remember the formula, the tutorial gives you tips on other...
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Activity
University of Saskatchewan (Canada)

University of Saskatchewan: Geometry

For Students 9th - 10th Standards
The University of Saskatchewan's Department of Mathematics and Statistics provides high school students with online tutorials and exercises on what they deem some of the most important topics in geometry: Triangles, and Circles and Other...
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Activity
Varsity Tutors

Varsity Tutors: Hotmath: Practice Problems: Right Triangles and Trigonometry

For Students 9th - 10th Standards
Twenty-five problems cover the topic of right triangles and trigonometry in different settings. They are given with each step to the solution cleverly revealed one at a time. You can work each step of the problem then click the "View...
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Activity
TeachEngineering

Teach Engineering: Trig River

For Teachers 6th - 8th
Students learn about and use a right triangle to determine the width of a "pretend" river. Working in teams, they estimate of the width of the river, measure it and compare their results with classmates.
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Unit Plan
National Council of Teachers of Mathematics

The Math Forum: Triangle Formulas

For Students 9th - 10th
Investigate the geometric definitions of triangles, focusing upon equilateral, isosceles, right, and scalene with detailed drawings and appropriate formulas for each. This site has links to more information on triangles.
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Activity
Oswego City School District

Regents Exam Prep Center: Special Right Triangles

For Students 9th - 10th
A collection of lessons, practice activities, and a teacher resource that will aid your exploration and understanding of special right triangles.
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Lesson Plan
Oswego City School District

Regents Exam Prep Center: Special Right Triangles 30 60 90

For Teachers 9th - 10th
This tutorial shows two special formulas that are used to determined the measures of the legs of 30-60-90 triangles. And if you can't remember the formula, the tutorial gives you tips on other methods you can use.
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Unit Plan
Oswego City School District

Regents Exam Prep Center: Mean Proportional in a Right Triangle

For Teachers 9th - 10th
Material to supplement classroom instruction on mean proportional in a right triangle: a lesson with a definition of "mean proportional" as well as theorems with examples; an online multiple-choice quiz with answers; and guidelines for...
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Activity
Shodor Education Foundation

Shodor Interactivate: Triangle Explorer

For Students 9th - 10th Standards
This applet allows users to study the nature of triangles and their area. It draws random triangles on a Cartesian coordinate system. The user can determine the area of the triangle using his or her preferred method. After the calculated...
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Interactive
Government of Alberta

Learn Alberta: Math Interactives: Exploring the Pythagorean Theorem

For Students 6th - 8th
This multimedia Learn Alberta math resource looks at the structural design of buildings and how the Pythagorean Theorem is often involved in the design process. The accompanying interactive component asks students to build a variety of...
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Unit Plan
Cuemath

Cuemath: Pythagoras Theorem

For Students 9th - 10th Standards
In this lesson, you will learn about the Pythagoras theorem, its derivations, and equations followed by solved real-world problems on the Pythagoras theorem triangle and squares.
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Activity
Math.com

Math.com: Pythagorean Theorem and Right Triangle Facts

For Students 6th - 8th Standards
The lesson investigates right triangles and the Pythagorean Theorem. Definitions, examples, and a worksheet are available.
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Activity
Texas Instruments

Texas Instruments: Investigating Segments in a Right Triangle

For Teachers 9th - 10th Standards
In this activity, students review definitions of terms such as right triangle, hypotenuse, midpoint, vertices, and equidistant. They also discover an important characteristic of the midpoint of the hypotenuse.