Lesson Exchange: Trig Functions to Find Sides of Triangle (Senior, Mathematics)

Something for young mathematicians to remember: the sum of any two sides must be greater than the third. Class members investigates the Triangle Inequality Theorem to find the relationship between the sides of a triangle. At the same...

Can any three lengths make a triangle? One of the videos in a playlist on basic geometry introduces the Triangle Inequality Theorem. Using three given lengths, the presentation illustrates the restrictions on lengths of any side of a...

Judging by the sides, things appear similar. A portion of a larger playlist on geometry introduces the Side-Side-Side Similarity Theorem. The video shows how to use the lengths of sides to determine whether triangles are similar.

Crossing into the realm of geometry with this video, Sal introduces the Pythagorean Theorem to viewers. He uses several examples (and right triangles) to illustrate the uses and application of the Pythagorean Theorem.

The Pythagorean Theorem works for something other than right triangles; show your class all it can do. Using information from the Pythagorean Theorem, the video shows how to determine whether a triangle is an acute or obtuse triangle....

Gimme three sides, mister! The video introduces the Side-Side-Side Triangle Congruence Theorem. Using segments of different lengths, the portion of a larger playlist on geometry shows that only one triangle can be built.

Teach your class how to solve problems using the triangle sum theorem. In this geometry lesson, high schoolers identify the missing angles in a triangle using the sum theorem. They graph triangles on the TI and moves the sides around to...

Identify triangles by their angle measures and side lengths by looking at and measuring angle measures and side lengths. Use Cabri Jr. to construct various triangles, then manipulate the construction to create the 6 types of triangles,...

Need to find the length of a side of a right triangle? Just use the Pythagorean Theorem! Follow along as the tutor defines the Theorem, explains how it works, then uses it to determine the missing length of a right triangle. 

High schoolers investigate the relationship between angle measures and sides of a triangle and the relationships among the three sides of a triangle. The use of technology (Cabri, Jr.) allows learners to make and test conjectures as they...