Not all triangles are created equal. A simple hands-on activity has learners investigate the side lengths of triangles. They use pipe cleaners to determine whether triangles of given side lengths can exist and then use the results to...

Learners estimate and measure triangles. In this geometry instructional activity, 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.

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...

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

Pupils identify properties of triangles. In this geometry lesson, students create triangles using three different segments. They make conjectures and predictions.

Young scholars investigate the Napoleon triangle theory. In this polygon lesson, students  differentiate between the boundary points, interior and lattice point of a polygon. They apply concepts of equilateral triangles to...

Pupils explore the concept of triangle inequalities.  In this triangle inequality lesson, students cut spaghetti noodles into given lengths.  Pupils use the noodles to complete a worksheet about triangle inequalities. ...

Young scholars apply properties of right triangles to solve problems. In this geometry instructional activity, students identify axioms and theorems using examples.

What did the triangle say to the circle? You're pointless! Class members will get the point when they investigate relationships between side lengths of a triangle using the Triangle Inequality Theorem. Pupils then create an...

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...

Properties about triangles are explored in this lesson. Geometers make conjectures about the length of a triangle's sides, the length of the angles in relation to the length of the sides, and the measure of the exterior angles of a...

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...

Tenth graders investigate the theorems of angles and lines to prove triagle sum theorem. 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...

Students explore the application of Hinge Theorem. In this geometry lesson, students write inequalities, given two sides of a triangle. They solve problems with triangular inequalities using the proper theorem.

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

How do you build a polygon from an inequality? An engaging lesson challenges pupils to do just that. Building from the previous lesson in this series, learners write systems of inequalities to model rectangles, triangles, and even...

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

Learners identify the pattern in a problem. In this geometry instructional activity, students make predictions, collect and analyze data. They apply the idea of scales and measurements to the real world.