Shodor Education Foundation
Triangle Area
While the lesson plan focuses on right triangles, this activity offers a great way to practice the area of all triangles through an interactive webpage. The activity begins with the class taking a square paper and cutting in in half; can...
EEWeb
Geometry: Shapes and Solids
An excellent resource for a geometry class, as well as for an electrical engineering course. A thorough reference sheet covers geometric shapes such as triangles, parallelograms, and circles, as well as 3-D shapes and the Pythagorean...
Teach Engineering
Stay in Shape
Using their knowledge of right triangles, pupils find out how far a ship is from a light house. Class members determine how far around the world a ship would be sailing at a constant speed.
Curated OER
To Be a Triangle Or Not To Be a Triangle?
In this triangles worksheet, 10th graders solve and complete 10 different problems that include applying the Triangle Inequality Theorem. First, they use the illustrated triangles and the data table to test the theorem. Then, students...
Curated OER
Finding the Area of an Equilateral Triangle
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...
Curated OER
The Truth About Triangles And Proofs
Students engage in a lesson that is about the classification of triangles and the mathematical proofs involved in working with them. They work on a variety of problems that are created by the teacher with the focus upon the importance of...
Curated OER
What Is Hyperbolic Geometry?
Ninth graders discuss the concept of hyperbolic geometry. They complete Internet geometry activities and write essays comparing and contrasting hyperbolic geometry to Euclidean geometry.
Mathematics Assessment Project
Solving Problems with Circles and Triangles
After completing a task involving examining the ratio of areas of triangles and circles in a given figure, scholars examine sample responses to identify other strategies they could use to solve the problem.
Curated OER
Isosceles Triangle Theorem
In this geometry worksheet, students differentiate between regular triangles and isosceles triangles. They apply the converse theorem and the vertex angle. There are eleven questions with an answer key.
Curated OER
Isosceles Right Triangle
In this isosceles right triangle worksheet, 10th graders solve and complete 5 different constructions of composition and decomposition. First, they make 4 congruent isosceles triangles with the model on the left. Then, students create...
Curated OER
Geometry In Space
How can we identify shapes in the Universe? High schoolers will compare and contrast elliptic and hyperbolic geometry. They will also explore one possible way to measure the curvature of the Universe, namely, by measuring the sum of the...
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...
Bytes Arithmetic
Geometry Pad+
Graphing paper, pencil, ruler, protractor, and compass, all get replaced or supplemented with this dynamic geometry application. Here, you can create, move, and scale many different shapes, as well as, explore and change their properties...
Curated OER
Patterns in Pascal's Triangle
Students examine the patterns in Pascal's Triangle. In this recognizing lesson, students view a model of Pascal's Triangle and describe the patterns of the multiples. Students identify the shapes that are made within Pascal's Triangle.
CK-12 Foundation
Angle-Angle-Side Triangles: Garden Gate
Good fences make good gardens. Individuals use an interactive to see how angles and sides relate in a triangular-shaped garden fence. They apply the Law of Sines to find the length of the garden gate (third side of triangle) given two...
Mathematics Vision Project
Module 5: Modeling with Geometry
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 to finding...
Mathematics Vision Project
Module 6: Connecting Algebra and Geometry
A geometry module connects algebraic reasoning to geometry. It challenges scholars to investigate the slope criteria for parallel and perpendicular lines, prove theorems involving coordinate geometry, and write equations for circles and...
Curated OER
Napolean Triangle
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 solve problems.
Curated OER
Geometry Regents Questions: Isosceles Triangle Theorem
In this isosceles triangle worksheet, students solve 19 multiple choice and short answer problems. Students use the isosceles triangle theorem to determine unknown angle measures.
Illustrative Mathematics
Placing a Fire Hydrant
Triangle centers and the segments that create them easily become an exercise in memorization, without the help of engaging applications like this lesson. Here the class investigates the measure of center that is equidistant to the three...
Curated OER
Basic Shapes
Students create books about shapes. For this shape lesson, students select a topic such as points, lines, angles, planes, polygons, quadrilaterals, triangles, circles, and polyhedra. In groups, they create an illustrated children's...
Curated OER
Geometry Practice: Area of Polygons #8
In this area of polygons worksheet, learners solve 7 short answer and multiple choice questions about area. Students find the area of triangles given base and height, or points in the coordinate plane.
Curated OER
Solve Word Problems with Geometry
In this geometry worksheet, learners solve word problems having to do with lines, angles, shapes, area, perimeter, and more. Students complete 57 problems total.
Curated OER
Constructions Triangles
Learners explore the difference between a construction and a drawing. They focus on various ways to construct different types of triangles. The instructional activity is an application of Cabri Jr. and reinforces the difference between a...