Everyday Mathematics
Mathematics Within: Slope and Triangles
Learners discover a method for determining the slope of a line by creating and comparing similar triangles. They fold coordinate grids to make three similar triangles then measure the sides to compare the relationships between the...
Illustrative Mathematics
Joining Two Midpoints of Sides of a Triangle
Without ever using the actual term, this exercise has the learner develop the key properties of the midsegment of a triangle. This task leads the class to discover a proof of similar triangles using the properties of parallel lines cut...
Virginia Department of Education
Similar Triangles
Pupils work in pairs to investigate what it takes to prove that two triangles are similar. They work through various shortcuts to find which are enough to show a similarity relationship between the triangles. Small groups work with the...
Virginia Department of Education
Congruent Triangles
Is this enough to show the two triangles are congruent? Small groups work through different combinations of constructing triangles from congruent parts to determine which combinations create only congruent triangles. Participants use the...
West Contra Costa Unified School District
Congruence Through Transformations
Transform your lesson on transformations. Learners use given congruent triangles and tracing paper to determine the single transformation that carries one to the other. The concept is extended to combinations of transformations to...
Curated OER
Congruent Trianges - Is This Enough Information?
Seventh graders determine whether two triangles are congruent and provide an explanation to why they are not. They apply concepts of measurement of angles and collect evidence of congruent angles in the world.
EngageNY
Are All Parabolas Similar?
Congruence and similarity apply to functions as well as polygons. Learners examine the effects of transformations on the shape of parabolas. They determine the transformation(s) that produce similar and congruent functions.
Curated OER
Congruent and Similar figures
Eighth graders explore congruent and similar figures. For this eighth grade geometry lesson, 8th graders use geoboards to create congruent and similar figures and explore the relationships between the sides and angles.
Curated OER
Proofs of the Pythagorean Theorem
Working individually and collaboratively, geometers gain a clear understanding of the Pythagorean theorem. They create, explain, and compare proofs of the theorem. Proofs involve areas of trapezoids, squares, and triangles, congruent...
Curated OER
An Application of Congruence
Learners solve triangles using the properties if congruency. In this geometry lesson, students apply congruent and similar figures to solve real world and math problems. They show they are able to follow instructions.
Curated OER
CSI Investigation of Congruence and Similarity
Students differentiate between similarity and congruence using polygons. In this geometry lesson, students label triangles based on their properties. They find missing sides and angles using the interior sum theorem.
Curated OER
Congruent Triangles - Is This Enough Information?
Seventh graders examine congruence postulates and apply knowledge to triangles in the world around them.
Curated OER
The Pythagorean Theorem Lesson 2
Learners discuss and review examples of the Pythagorean Theorem using a GSP, Geometer's Sketchpad, activity.
Education Institute
Four Mathematics Lessons for Grade 9
These four lesson plans build algebra skills for working with numbers in exponential form and for examining triangles. Be aware that in the text, scientific notation is referred to as index notation and the laws of exponents as the laws...
West Contra Costa Unified School District
Conics Introduction and Parabolas
Where did conic sections get their name? The equation and graph of a parabola are developed from the definition of the conic section. Teacher examples on graphing the equation and writing an equation from the graph round out the plan.
Curated OER
Arts Impact and Math
Third graders incorporate math into dancing. In this algebra lesson, 3rd graders identify different shapes and patterns using dance movements. They relate the different creations to polygons as they incorporate the use of stretchy bands...
Curated OER
Algebra/Geometry Institute: Area of Polygons
Students find the area of polygons. For this area of polygons lesson, students find the area of parallelograms, rectangles, squares, and other polygons. They identify each given figure and determine the appropriate formula needed to...
EngageNY
Writing and Solving Linear Equations
Incorporate geometry into the solving linear equations lesson. Pupils use their knowledge of geometry to write linear equations which reinforces geometry measurement concepts while at the same time providing a familiar context for...
Curated OER
Transformations: Reflections
Young scholars perform transformations on their graphs. In this algebra lesson, students identify the pre-image and image. They find and identify congruent shapes and isometry.
Curated OER
Introduction to Fractals: Geometric Fractals
Students study and observe the patterns made by the areas of the Sierpinski Triangle. Students use the computer to draw two or three iterations to discover the number patterns. Students complete worksheets based on Geometric Fractals.
Curated OER
Slope Right Up
Middle schoolers use triangles to find the length and slope of each side. After connecting the vertices, they add points based on their specific instructions. They use the Pythagorean Theorem to complete a worksheet to end the lesson.
Curated OER
Geometry and Measurement
Middle schoolers 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. Middle schoolers use pegboards and...
Curated OER
Pythagorean Theorem by Graphic Manipulation
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...
Curated OER
Quilting Geometry
Study geometry through the concept of quilt design. High schoolers examine the geometric shapes in various quilts and then create their own quilts using geometric shapes that fit together. In the end, they write a paragraph to describe...