Read about Triangles, and then play with them here. They rotate, too! So you can become familiar with them from all angles.

A click and drag interactive activity on a triangle's angles, sides and how the measurements of each relate--color coded for clarity.

Interactive, free online geometry tool from GeoGebra: create triangles, circles, angles, transformations and much more!

What triangles can you create using the red, green, and blue side lengths? Adjust the lengths of the sides by dragging the endpoints. Adjust the angles in the triangle by dragging the endpoints along the circles.

Proving Triangles Congruent (2): One Step Transformations; Constructing a Regular Hexagon + Practice; Transformations: 2 Steps (V1)

Simultaneously display a free triangle and a constrained triangle. Apply constraints and manipulate the second triangle, then compare both triangles to see the effects. Return the constrained triangle to the same state as the unconstrained one at …

Linear Equation (interactive line with various features) Linear Inequality. System of Linear Inequalities; Ordered Pairs; Parallel Lines Cut by a Transversal (and all the angles: corresponding, alternate interior and exterior) Parallelogram (fully interactive, see properties change in real time)

Graph functions, plot points, visualize algebraic equations, add sliders, animate graphs, and more.

Graph functions, plot points, visualize algebraic equations, add sliders, animate graphs, and more.

Get ready to put your fifth grade students' geometry skills to the test with this interactive math lesson from iKnowIt.com! In this online geometry game, students will practice classifying triangles as equilateral, isosceles, or scalene.