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...

How many different types of triangles can your class name? A discovery lesson guides learners through an exploration of the different triangle types and the relationships between their angles and sides. Using coordinate geometry,...

Learners identify the properties of an isosceles triangle. In this geometry lesson, students find the midpoint, median and angle bisector of a triangle. They construct angle bisectors and measure missing angles.

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,...

Learners explore the difference between a construction and a drawing. They focus on various ways to construct different types of triangles. The lesson is an application of Cabri Jr. and reinforces the difference between a constructions...

How do you know if a pair of triangles are congruent? Use the instructional activity to help class members become comfortable identifying the congruence criteria. They begin with an exploration of ASA and SSS criteria through...

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

Students solve problems with isosceles triangles. In this geometry lesson, students identify and use the properties of triangles to solve their problems. They find the median, altitude, and angles to the triangles.

Solids come in many shapes and sizes. Using geometry, scholars create two-dimensional cross-sections of various three-dimensional objects. They develop the lesson further by finding the volume of solids. The module then shifts...

Students identify different types of special right triangles. In this geometry lesson, students differentiate between right triangles and isosceles triangles. they construct the triangles using geometry software and make conjectures...

You're safe, when calculating the odds of stealing second base! Learners compare the rate of a runner to the distance the ball travels, in a lesson that explores right triangles and measurement. Full of discussion questions and fun...

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

Divide and conquer the geometry problem. Young scholars consider how to subdivide triangles into smaller ones that have equal areas. They must apply their knowledge of medians to help accomplish the task.

Stretch your mind about triangles. Given a triangle, scholars consider a smaller triangle formed when they stretch three rubber bands from each vertex to the opposite side. They determine the ratios of the areas and perimeters of the...

Second graders explore the features of triangles and quadrilaterals. In this lesson on triangles and quadrilaterals, 2nd graders rotate with their group to five different activities all exploring a different aspect of geometry.

Fourth graders explore obtuse triangles. In this geometry lesson, 4th graders make obtuse triangles with paper and scissors. They determine how to find the center of their triangle.

High schoolers construct perpendicular bisectors using Cabri Jr. on their graphing calculator. They then construct conditional statements about perpendicular bisectors along with their converse, inverse, and contrapositive.

What do you do when you don't think you have enough information? You look for another way to do the problem! Pupils combine what they know about finding the area of a triangle and trigonometry to determine triangle area when they don't...

Students identify missing sides and angles. In this geometry lesson, students use triangular theorems to identify the missing sides. They use the Pythagorean Theorem to find the different ratios of each side.

Students investigate the Pythagorean Theorem. For this geometry lesson, students define angles and sides of right triangles. They calculate the area and surface area using formulas derived by the Pythagorean Theorem.

Students classify different types of triangles. For this geometry lesson, students identify and use properties of triangles. They differentiate between isosceles and equilateral triangles.

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

Students investigate the interior angles of a triangle. For this geometry lesson, students create the formula to calculate the angles inside a triangle. They observe the total sum of a triangles angle on the navigator.

Junior geometers use hands-on manipulatives to explore and describe the properties and attributes of a fundamental polygon, the triangle. They learn different kinds of angles and their measurements. This well-written lesson plan provides...