National Security Agency
Classifying Triangles
Building on young mathematicians' prior knowledge of three-sided shapes, this lesson series explores the defining characteristics of different types of triangles. Starting with a shared reading of the children's book The Greedy Triangle,...
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...
Illustrative Mathematics
Lines of Symmetry for Triangles
What can symmetry tell us about triangles? After looking at four examples, learners will come to realize that lines of symmetry are different for equilateral, isosceles, and scalene triangles. Use this guided practice activity as an...
Texas Instruments
Identifying a Triangle by its Sides and 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,...
Digging Into Math
Classifying Triangles
Young mathematicians explore the world of three-sided shapes in this lesson on the different types of triangles. Starting with a general introduction to classification using Venn diagrams, children learn how to categorize triangles based...
Willow Tree
Surface Area of Three-Dimensional Figures
Lateral area and surface area are simple concepts, but calculating them is not as easy! Using formulas, learners calculate lateral area and surface area for the same three-dimensional figures. The resource discusses the formula variables...
Curated OER
SuperShapes, Part 1; "Tri"ing Triangles
An outstanding lesson on triangles awaits your math scholars. Learners focus on the triangle, which is the strongest of all polygons. They see the role that triangles play in the design of buildings, and learn about triangle...
Curated OER
Geometric Figures-Triangles
Fourth graders explore triangles. For this math lesson, 4th graders discuss the different types of triangles. Students create triangles using wiki sticks. Students complete an online matching game.
Curated OER
Draw 3 Dimensional Objects
Bring three-dimensional shapes to life in your classroom. First introduce the vocabulary of three-dimensional shapes, such as sphere, cube, and pyramid. Then, show your kids examples of how to use two-dimensional objects draw...
Curated OER
Classifying Triangles by the Length of the Sides Using Cabri Jr.
Learners follow detailed directions to create triangles on their graphing calculator. In this properties of triangles lesson, they will create triangles on their calculators using the Cabri Jr. application. They then identify three...
Curated OER
Triangles
Fourth graders participate in three experiments to gain understanding of triangles. In this triangles lesson, 4th graders use pipe cleaners to create bubble pipes, basketball hoops and bingo cards to display the characteristics of...
Willow Tree
Three-Dimensional Figures
Time to move into the third dimension! Learn the names of the geometric solids and count faces, edges, and vertices. Then learn to recognize nets that create a given solid.
Curated OER
Triangle Congruence with Coordinate
Two triangles are displayed on a coordinate plane. Youngsters apply a reflection and a translation to demonstrate their congruence. This exercise makes a terrific tool for teaching these concepts, or a way to assess learning.
Centers for Disease Control and Prevention
Understanding the Epidemiologic Triangle through Infectious Disease
Introduce infectious diseases and the epidemiologic triangle. A helpful resource describes the agent, host, and environment from the three vertices as well as the time factor, which is in the middle. Scholars complete a simple...
Curated OER
Congruent Triangles Postulates
Students discover three lettered postulates that prove triangles congruent.
Curated OER
Drawing a Triangle with Cabri Junior
Learners draw triangles on their graphing calculators using the Cabri Junior application. In this graphing calculator lesson, students follow step by step directions to create triangles on their calculator. They identify the type of...
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.
Curated OER
Travel Triangles
Students demonstrate and understanding of the three types of angles using triangles and quadrilaterals. In this angles lesson plan, students learn about acute, obtuse and right angles. They use cut-outs to find the areas of triangles and...
Curated OER
Triangles
Students identify triangles in the real world and construct their own triangle using drinking straws. They explore abstract triangles and find additional geometric shapes such as trapezoids. Students discuss similar shapes and examine...
Curated OER
Types of Triangles
Students classify triangles by the length of their sides. In this geometry lesson, students use a white board to demonstrate the angles of various triangles. Students construct an equilateral, isosceles, and a scalene triangle.
Curated OER
2-D polygons
A hands-on activity uses the Zome modeling system, and helps young geometers either learn or review their knowledge of polygons. Students build as many different 2-dimensional polygons as possible: triangle, square, rectangle, pentagon,...
Curated OER
Everyday Heroes You Can Be One, Too
Students listen to a read aloud of Alan Baker's, White Rabbit's Color Book while identifying shapes and lines throughout the book. They use shapes and different types of lines to create a bunny of their own. They must use five shapes to...
Curated OER
Triangles
Learners discover the difference between triangles. In this triangle lesson plan, students discuss the different types of triangles, then draw the three different types of triangles. The teacher will draw, or model, how to draw the...
Curated OER
Scalene Triangles
Fifth graders identify and classify scalene, equilateral, and isosceles triangles. In this triangle activity, 5th graders define the different attributes of 3 types of triangles and sort them by descriptions and comparisons. Students...