+
Unit Plan
Math Open Reference

Math Open Reference: Triangles

For Students 9th - 10th Standards
A complete reference guide to types of triangles and triangle perimeter and area. It provides definitions and interactive animated activities that enhance further explanation.
+
Handout
Analyze Math

Analyze Math: Free Math Tutorials: Triangles

For Students 9th - 10th Standards
The geometry tutorial investigates the definitions and properties of triangles. Topics included are isosceles, equilateral, and right triangles. In addition, the sine and cosine laws of triangles are defined.
+
Unit Plan
CK-12 Foundation

Ck 12: Trigonometry: Pythagorean Theorem for Solving Right Triangles

For Students 10th - 12th Standards
[Free Registration/Login may be required to access all resource tools.] This lesson applies the trigonometric ratios and their inverses to real-life situations.
+
Unit Plan
CK-12 Foundation

Ck 12: Trigonometry: Special Triangle Ratios

For Students 10th - 12th Standards
[Free Registration/Login may be required to access all resource tools.] Use right triangle ratios to solve for sides of triangles.
+
Activity
Exploratorium

Exploratorium: Ilion High: Build a Clinometer

For Students 9th - 10th Standards
Instructions for building a clinometer are given on this page. Clinometers can be used to measure the angle of elevation of a right triangle, and in turn find the height of large objects.
+
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.
+
Handout
CK-12 Foundation

Ck 12: Geometry: Right Triangle Similarity Study Guide

For Students 9th - 10th Standards
[Free Registration/Login may be required to access all resource tools.] An overview of altitudes and geometric mean is provided in this study guide.
+
Unit Plan
CK-12 Foundation

Ck 12: Geometry: Comparing Angles and Sides in Triangles

For Students 9th - 10th Standards
[Free Registration/Login may be required to access all resource tools.] This concept teaches students the relationship between opposite angles and sides in triangles and how to use this relationship to compare triangles. students examine...
+
Unknown Type
Khan Academy

Khan Academy: Solve for a Side in Right Triangles

For Students 9th - 10th Standards
Given one side length and an acute angle in a right triangle, find another side using trigonometry. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
+
Handout
Math Open Reference

Math Open Reference: Isosceles Triangle

For Students 9th - 10th Standards
A reference guide to isosceles triangles. It provides a definition and interactive animated activity that enhances further explanation. Includes links to related topics.
+
Handout
Math Open Reference

Math Open Reference: Obtuse Triangle

For Students 9th - 10th Standards
A reference guide to obtuse triangles. It provides a definition and interactive animated activity that enhances further explanation.
+
Handout
Math Open Reference

Math Open Reference: Equiangular Triangle

For Students 9th - 10th Standards
Explore equiangular triangles with this handy reference guide. Provides a detailed definition, examples, and an interactive that enhances further explanation. Includes links to related topics.
+
Handout
Math Open Reference

Math Open Reference: Acute Triangle

For Students 9th - 10th Standards
Explore acute triangles with this handy reference guide. Provides a detailed definition and an interactive activity that enhances further explanation. Includes links to related topics.
+
Handout
Geometry Help

Geometry Help: Similar Triangles

For Students 9th - 10th Standards
Explains the basic concept of similar triangles with step-by-step instructions and methods for solving specific problems on your own relating to this topic.
+
Handout
Geometry Help

Geometry Help: Right Triangles

For Students 9th - 10th Standards
Explains the basic concept of right triangles with step-by-step instructions and methods for solving specific problems on your own relating to this topic.
+
Handout
Geometry Help

Geometry Help: Equilateral Triangles

For Students 9th - 10th Standards
Explains the basic concept of equilateral triangles with step-by-step instructions and methods for solving specific problems on your own relating to this topic.
+
Handout
Geometry Help

Geometry Help: Congruent Triangles

For Students 9th - 10th Standards
Explains the basic concept of congruent triangles with step-by-step instructions and methods for solving specific problems on your own relating to this topic.
+
Handout
Geometry Help

Geometry Help: Triangles

For Students 9th - 10th Standards
Explains the basic concept of triangles with step-by-step instructions and methods for solving specific problems on your own relating to this topic.
+
Unit Plan
Cuemath

Cuemath: Congruent Triangles

For Students 9th - 10th Standards
Explore the world of congruent triangles in this mini-lesson. Provides a definition and examples that help with understanding their properties. Includes a short video and practice questions with answers.
+
Handout
Math Open Reference

Math Open Reference: Congruent Triangles

For Students 9th - 10th Standards
A complete reference guide to congruent triangles. It provides definitions, examples, and an interactive activity that enhances further explanation. Includes links to related topics.
+
eBook
CK-12 Foundation

Ck 12: Interactive Geometry: 6.3 Aa Triangle Similarity

For Students 9th - 10th Standards
If two triangles are similar, it means that all corresponding angle pairs are congruent and all corresponding sides are proportional. However, in order to be sure that two triangles are similar, you do not necessarily need to have...
+
eBook
CK-12 Foundation

Ck 12: Interactive Geometry: 17.4 Inverse Trigonometric Ratios

For Students 9th - 10th Standards
Define the trigonometric ratios in terms of ratios of the sides of a right triangle.
+
eBook
CK-12 Foundation

Ck 12: Interactive Geometry: 6.7 Applications of Similar Triangles

For Students 9th - 10th Standards
Learn how similar triangles have congruent corresponding angles and proportional corresponding sides.
+
eBook
CK-12 Foundation

Ck 12: Interactive Geometry: 6.5 Sss Triangle Similarity

For Students 9th - 10th Standards
Explore and understand two triangles that are similar.