Handout
CK-12 Foundation

Ck 12: Geometry: Special Right Triangles Study Guide

For Students 9th - 10th Standards
[Free Registration/Login may be required to access all resource tools.] Different types of right triangles and trigonometric ratios for special right triangles are covered in this study guide.
Unit Plan
CK-12 Foundation

Ck 12: Trigonometry: Lengths of Sides in Isosceles Right Triangles

For Students 10th - 12th Standards
[Free Registration/Login may be required to access all resource tools.] Here you'll learn what an isosceles right triangle is, the relationships between the sides of an isosceles right triangle, and how to find the length of an unknown...
eBook
CK-12 Foundation

Ck 12: Algebra Ii: 4.2 Right Triangle Trig Extended to Circles With a Model

For Students 9th - 10th Standards
This section explores the relationship between right triangles, circles, and trigonometry. It investigates how a right triangle that is set inside a circle and rotates around the circle is connected to trigonometric functions and their...
eBook
Mathigon

Mathigon: Geometry: Triangles and Trigonometry: Properties of Triangles

For Students 9th - 10th Standards
This lesson focuses on the properties of triangles, a closed shape that has three sides, three vertices, and and three internal angles. There are different types of triangles such as a right triangle, obtuse, and acute based on the...
Unit Plan
Cuemath

Cuemath: Altitude of a Triangle

For Students 9th - 10th Standards
Explore the world of the altitude of a triangle in this mini-lesson including its definition, altitudes in different types of triangles, formulae, some solved examples, and a few interactive questions for you to test your understanding.
Unit Plan
Oswego City School District

Regents Exam Prep Center: Area of a Triangle and Parallelogram Using Trig

For Students 9th - 10th Standards
How can trigonometry be used to find the area of a triangle or parallelogram? Does the triangle need to be a right triangle, and how accurate can the results possibly be? The answers to these questions are found here along with several...
Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Co Classifying Triangles

For Teachers 9th - 10th Standards
The goal of this task is to help students synthesize their knowledge of triangles where only two of the vertices have been given. They will need to know that a triangle inscribed in a circle, with a diameter of the circle as one side, is...
Activity
Shodor Education Foundation

Shodor Interactivate: Squaring the Triangle

For Students 6th - 8th Standards
Students explore the relationship between the Pythagorean Theorem and right triangles. Teacher resources are included.
Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: F Tf Special Triangles 1

For Teachers 9th - 10th Standards
Using known facts about the unit circle and isosceles triangles together with the Pythagorean Theorem, learners can derive the sine and cosine of special angles. Aligns with HSF-TF.A.3.
Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: F Tf Special Triangles 2

For Teachers 9th - 10th Standards
Using known facts about the unit circle and isosceles triangles together with the Pythagorean Theorem, students can derive the sine and cosine of special angles. Aligns with HSF-TF.A.3.
Handout
Math Open Reference

Math Open Reference: Circumcircle of a Triangle

For Students 9th - 10th Standards
A complete reference guide to the circumcircle of a triangle. It provides definitions, examples, and an interactive activity that enhances further explanation. Includes links to related topics.
Unit Plan
Other

Algebra Lab: Word Lesson: Vectors Right Triangles Components and Resultants

For Students 9th - 10th Standards
Solve problems using vectors that involve velocity, speed, direction, and magnitude. Includes examples and practice problems. Click on the buttons under the practice questions to see the solutions.
eBook
CK-12 Foundation

Ck 12: Algebra Ii: 4.1 Revisiting Right Triangle Trigonometry

For Students 9th - 10th Standards
Use this tutorial to revisit right triangle trigonometry.
Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: 8.g Pythagorean Theorem in Mathematical Context

For Teachers 8th Standards
Eighth graders are shown a drawing of a rectangle with a central triangle bordered by three right triangles. They are asked to prove whether or not the middle triangle is also a right triangle. Aligns with 8.G.B.
Activity
Shodor Education Foundation

Shodor Interactivate: Interactive: Pythagorean Explorer

For Students 6th - 8th Standards
Students find the length of a side of a right triangle by using the Pythagorean Theorem and then check their answers.
Interactive
Shodor Education Foundation

Shodor Interactivate: Squaring the Triangle

For Students 9th - 10th Standards
Learn about how the Pythagorean Theorem works through investigating the standard geometric proof.
eBook
Mathigon

Mathigon: Geometry: Triangles and Trigonometry: Pythagoras' Theorem

For Students 9th - 10th Standards
Pythagoras' Theorem: In any right-angled triangle, the square of the length of the hypotenuse (the side that lies opposite the right angle) is equal to the sum of the squares of the other two sides. (A+B=C)
eBook
CK-12 Foundation

Ck 12: Algebra Ii: 1.10 Pythagorean Triples

For Students 9th - 10th
This section explores right triangles with three lengths that are considered Pythagorean Triples, and also investigates how some right triangles can have lengths that are not Pythagorean Triples.
Interactive
Shodor Education Foundation

Shodor Interactivate: Pythagorean Explorer

For Students 9th - 10th Standards
Calculate the length of one side of an automatically generated right triangle by using the Pythagorean Theorem, and then check your answers.
Article
Mocomi & Anibrain Digital Technologies

Mocomi: Types of Triangles

For Students 2nd - 8th Standards
Explore the different types of triangles and other properties.
Lesson Plan
Illustrative Mathematics

Illustrative Mathematics: G Gpe.5 Triangles Inscribed in Circle

For Teachers 9th - 10th Standards
In this task, students use ideas about linear functions to determine when certain angles are right angles. They use the fact that two lines (if not vertical or horizontal) are perpendicular when their slopes are inverse reciprocals, as...
Interactive
Doina Popovici

Math Play: Pythagorean Theorem Jeopardy Game

For Students 6th - 9th Standards
This jeopardy-style game will have students calculate the sides of a right triangle by using the Pythagorean Theorem.
Lesson Plan
Homeschool Math

Homeschool Math: Area of Parallelograms

For Teachers 6th - 7th Standards
This lesson plan presents the idea that the area of any right triangle is exactly half of a certain rectangle, and contains varied exercises for students.
Handout
Purple Math

Purplemath: The Pythagorean Theorem

For Students 9th - 10th Standards
Defines the Pythagorean Theorem, and demonstrates how to use this Theorem in connection with right-angled triangles.

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