Curated OER
Indirect Proof and Inequalities in one Triangle
For this geometry worksheet, 10th graders complete an indirect proof and order the sides or angles of a triangle. Also, students determine if a triangle can have sides with the given lengths. The two page worksheet contains twelve...
Curated OER
To Be a Triangle Or Not To Be a Triangle?
In this triangles worksheet, 10th graders solve and complete 10 different problems that include applying the Triangle Inequality Theorem. First, they use the illustrated triangles and the data table to test the theorem. Then, students...
Curated OER
Triangle Inequality
Students discover that the sum of the lengths of any two sides of a triangle must be greater than the third side. They are shown how a triangle is formed using three strips such as that the triangle is seen inside the strips.
Curated OER
Triangle Inequality Theorems Investigation
Students estimate and measure triangles. In this geometry lesson, students identify the relationship between three sides and a triangle. They use the inequality theorem to decide if a triangle will be formed or not.
Curated OER
Solving Problems Using Triangle Inequality Theorem
Sixth graders investigate triangles and the inequality theorem. They will collaborate in groups to determine the length of a longest side of a triangle. Then relate the size of the triangle to its angles using protractors, yard sticks,...
Curated OER
Triangle Inequalities Homework
In this geometry worksheet, students solve problems based on the triangle inequality theorem(s) in which determine if the given lengths can form a triangle, given two sides of a triangle determine the range of the third side, and order...
Curated OER
Triangle Inequality Theorem
Students identify properties of triangles. For this geometry lesson, students create triangles using three different segments. They make conjectures and predictions.
Curated OER
Quiz: Triangle Inequality Theorem
In this triangle inequality theorem activity, students determine the lengths of the sides of triangles and identify the measure of angles. This one-page activity contains ten triangle theorem problems.
Curated OER
Drawing Straws
Fourth graders examine the Triangle Inequality Theorem by investigating possible lengths of the sides of a triangle.
Alabama Learning Exchange
Is It a Triangle?
High schoolers explore the concept of triangle inequalities. In this triangle inequality lesson, students cut spaghetti noodles into given lengths. High schoolers use the noodles to complete a worksheet about triangle inequalities. ...
Texas Education Agency
Texas Gateway: Making and Verifying Conjectures About Triangles
Given examples of triangles and their component parts, the student will use explorations and concrete models to verify and apply the and find the sum of interior angles.
Texas Instruments
Texas Instruments: Triangle Inequality Theorem
In this activity, students will explore the concepts underlying the Triangle Inequality Theorem by comparing side lengths and angle measures of a triangle. They will use an interactive construction to see why this theorem is true.
Texas Instruments
Texas Instruments: Triangle Inequality
In this activity the Students can use Cabri Jr. to investigate the Triangle Inequality Theorm and make conjectures about their findings.
University of Georgia
University of Georgia: Inter Math: Triangle Inequality
This site has a description of the triangle inequality theorem along with a visual representation, and animation explaining the triangle inequality rule with the radii of circles at the segment endpoints. Links to related terms, more...
Khan Academy
Khan Academy: Constructing Triangles
Given the lengths of two sides of a triangle, what can we say about the third side? Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Math Open Reference
Math Open Reference: Triangles
A complete reference guide to types of triangles and triangle perimeter and area. It provides definitions and interactive animated activities that enhance further explanation.
CK-12 Foundation
Ck 12: Geometry: Triangle Inequality Theorem
[Free Registration/Login may be required to access all resource tools.] This concept teaches students the Triangle Inequality Theorem and how to apply it.
CK-12 Foundation
Ck 12: Geometry: Triangle Inequality Theorem
[Free Registration/Login may be required to access all resource tools.] Apply the Triangle Inequality Theorem to determine if three side lengths make a triangle.
CK-12 Foundation
Ck 12: Geometry: Inequalities in Triangles Study Guide
This study guide on triangle inequalities discusses comparing angles and sides, the Triangle Inequality Theorem, and the Hinge Theorem. It is available for download with free registration.
Geometry Help
Geometry Help: Hinge Theorem
Provides a detailed definition of the Hinge Theorem with step-by-step instructions and methods for solving problems on your own.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Triangle Inequality
Dr. Math gives a hint of how to prove the triangle inequality theorem when answering a question posed about proving an absolute value problem using the triangle inequality theorem.