Four triangles are depicted for learners to construct on a geoboard. They compute and compare the areas, and so meet one of the sixth grade Common Core standards for geometry. Note that the set of triangles does not include a right...

This comprehensive web lesson describes how to classify triangles by their angle and side measurements. It provides real-world examples and exercises for students to practice the skill.

Here is a site that clearly and thoroughly explains the trigonometric functions of acute angles within a right triangle. There are example problems solved, problems for the student to attempt, and answers to the student problems. Point...

Students can practice classifying triangles based on angle measurements through a series of self-check exercises and timed learning games.

This lesson plan provides students with an opportunity to practice drawing and measuring triangles and angles. It also shows pictures and gives definitions of each type of angle and triangle.

This activity uses Cabri Jr to classify triangles according to their angle measure. [Requires Adobe Reader.]

In this activity, students investigate properties of triangles by randomly generating possible side lengths for triangles. They learn to determine if three line segments can form a triangle. They also learn to classify triangles as...

This site has an activity that displays several impossible triangles. The rules for triangles are also displayed. The student has to determine which rule has been violated for each impossible triangle.

Navigator Activity: This is a review of the right triangle in the coordinate plane. Given two lines (2 really nice ones) the students write the equation of the 3rd line to create a right triangle. They find the vertices of the triangle...

Students explore four types of angles in this interactive web lesson.

Students will be introduced to right triangle trigonometry. They will use the TI-89 and Geometer's Sketchpad to construct a right triangle and calculate sin, cosine, and tangent of various acute angles.

This site examines the six trigonometric functions from a right triangle point of view. Provides information, examples, and lots of exercises for understanding.

An introduction to solving acute and obtuse triangles by using the law of sines, including a derivation of the formula. Includes several pictures and examples.