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.

Students investigate the theorems of ASA, AAS, AAA and ASA. In this geometry lesson plan, 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...

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...

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, 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 by...

Looking at numerous examples of triangles, each with different properties, geometers develop their understanding of congruency. They use the notation of a counter-example to disprove certain conjectures and prove geometric theorems and...

Tenth graders explore congruent triangles.  In this geometry instructional activity, 10th graders investigate the conditions necessary to prove two triangles are congruent by SSS, ASA, AAS, or SAS. 

Your learners will make good use of the Socratic method in a collaborative task that begins with an assumed solution and ends with deeper understanding of the idea of determining two triangles congruent.

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...

Tenth graders explore congruent triangles.  In this geometry lesson, 10th graders investigate the conditions necessary to prove two triangles congruent.  The lesson combines dry erase board activities and the use of technology.

Tenth graders investigate the theorems of ASA, AAS, AAA and ASA. In this geometry lesson, 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 by...

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...

Students investigate angles of polygons. In this geometry lesson, students identify the relationship between angles and the number of sides in a polygon. They differentiate between sumilarity anf congruence in angles and sides.

Students differentiate between similarity and congruence using polygons. In this geometry lesson plan, students label triangles based on their properties. They find missing sides and angles using the interior sum theorem.

The problem seems simple: find the area of the equilateral triangle whose sides are each length 1. In fact, this same problem is solved in 8th grade, addressing a different Common Core standard, using the formula for area of a triangle...

Students investigate the relationship of triangles with its sides and angles. In this geometry instructional activity, students create visual on the graphing navigator as they study triangles. They move the sides around to create...

Students investigate the relationship between angles and their sides. In this geometry lesson, students prove why SSA does not work as a true angle side relationship theorem.

Students use the inequality theorem to solve triangles and their properties. In this geometry activity, students are given spaghetti of different lengths and asked to create triangles. They conclude the necessary length needed to make a...

Students identify and use the similarity theorem. For this geometry lesson, students differentiate between congruent and similar triangles. They solve problems using the computer modifying shapes by dragging.

Students differentiate between similar and congruent polygons. In this geometry lesson, students define the theorems and reasons for polygons similarity and congruence. They are given pictures and patterns to differentiate and identify.

Learners investigate triangles and congruences. In this geometry activity, students differentiate between inductive and deductive reasoning. They differentiate between similar and congruent triangles.

Circles are the foundation of many geometric concepts and extensions - a point that is thoroughly driven home in this extensive unit. Fundamental properties of circles are investigated (including sector area, angle measure, and...

Students view a right triangle displayed by the teacher. Students measure legs and the interior angles of the triangle. They look for a pattern or relationship between the legs and angles. Students use pegboards and string to create more...