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,...

Lead by example. Pupils use software to investigate given measures of sides and angles to determine whether they create congruent triangles. Using the discovered triangle congruences, learners put together proofs.

Through the examination of the relationship between the lengths of the sides of a triangles young scholars will learn the classification of triangles (acute, right, or obtuse).

There are many different ways to show a proof of the Pythagorean Theorem.  Here is a nice hands-on paper cutting activity that shows a graphic representation. You can even challenge your young Pythagoreans to come up with their own...

Students investigate the theorems of ASA, AAS, AAA and ASA. In this geometry lesson, students discuss the theorems of triangles and how it is used to solve for missing sides or angles. They review how two angles are formed by two rays...

Discover a new application of the Pythagorean Theorem. Learners prove and apply the converse of the Pythagorean Theorem in the 17th lesson plan in a 25-part series. The examples ask learners to verify right triangles using the...

Everyone's heard of Pythagoras, but who's Ptolemy? Learners test Ptolemy's Theorem using a specific cyclic quadrilateral and a ruler in the 22nd installment of a 23-part module. They then work through a proof of the theorem.

Prove the Pythagorean Theorem using multiple informal proofs. Scholars first develop an understanding of the origins of the Pythagorean Theorem through proofs. They round out the lesson plan by using the theorem to find missing side...

Transform your pupils into mathematicians as they learn to prove the popular Pythagorean Theorem. The 16th instructional activity in the series of 25 continues by teaching learners how to develop a proof. It shows how to prove the...

Students find triangular angles using the angle theorem. In this geometry lesson, students describe labeled triangles, use the pythagorean theorem, and rewrite information about triangles in standard form.

Angles and triangles: they're all connected. Uncover the connections between angles in triangles. Scholars learn how to find both exterior and interior angle measures in triangles. The lesson emphasizes the vocabulary related to these...

Starting with similar triangles and dilation factors, this unit quickly and thoroughly progresses into the world of right triangle features and trigonometric relationships. Presented in easy-to-attack modules with copious application...

Build confidence in proofs by proving a known property. Pupils explore two approaches to proving base angles of isosceles triangles are congruent: transformations and SAS. They then apply their understanding of the proof to more complex...

Tenth graders investigate the theorems of ASA, AAS, AAA and ASA. In this geometry lesson plan, 10th graders discuss the theorems of triangles and how it is used to solve for missing sides or angles. They review how two angles are formed...

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...

Learners estimate and measure triangles. For 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.

Students discover the Pythagorean Theorem.  In this discovering the Pythagorean Theorem lesson plan, students measure the lengths of various triangles to the nearest centimeter. Students record their measurements in a table. ...

Students calculate the different sides and angles of a triangle. In this geometry lesson plan, students use triangular properties to define the relationship between two triangle. They identify missing angles using the interior angle...

Students identify triangles as similar or congruent. In this geometry activity, students drag triangles around on the navigator to see the effect of different angles on the shape of the triangle. They discuss angle similarity and angle...

Learners find the different ratios of a triangle. In this geometry lesson, students use the Pythagorean Theorem to solve for missing sides and angles on a right triangle. They use a robot to create a right triangle.

Students draw a chart (included in the instructional activity) to use with their investigation. They review terminology of triangles and receive toothpicks to use in the instructional activity. Beginning with three toothpicks, students...

Students explore the history of Pythagoras and his contributions to mathematics. In this middle school geometry instructional activity, students use one inch tiles to investigate the Pythagorean Theorem and to find the length of the...

Students solve problems using the Pythagorean Theorem. In this geometry lesson, students identify different parts of a right triangle. They use the Pythagorean Theorem to calculate missing angles and sides.

Students investigate triangles and their relationship to each other. In this geometry lesson, students solve right triangles using the properties of the Pythagorean Theorem. They differentiate between right, acute, straight and oblique...