Learn and practice identifying and classifying triangles with interactive resources from GeoGebra.

Upper Elementary


Types of Triangles

Identify and classify triangles according to the measures of the interior angles and the lengths of the sides; relate triangles based upon their hierarchical attributes.

Middle School


Angle Sum Properties of Triangles, Quadrilaterals, and Polygons

Use a variety of triangles, quadrilaterals, and other polygons to draw conclusions about the sum of the measures of the interior angles.

Similar Triangles and Correspondence

Use properties of triangles to solve problems related to similar triangles and the relationships of their corresponding parts.

Triangle Inequality Theorem

Recognize conditions of side lengths that determine a unique triangle, more than one triangle, or no triangle.

Related Topics

Community Resources

Explore an extensive collection of over one million math and science activities, exercises and lessons meticulously crafted by our global GeoGebra community. Immerse yourself in the boundless possibilities that await you.

An illustration depicting an interconnected network of users around the globe

Get started using GeoGebra today

Create a free account so you can save your progress any time and access thousands of math resources for you to customize and share with others