National Security Agency
Classifying Triangles
Building on young mathematicians' prior knowledge of three-sided shapes, this lesson plan series explores the defining characteristics of different types of triangles. Starting with a shared reading of the children's book The Greedy...
McGraw Hill
Triangles
After reviewing characteristics of seven types of triangles, young geometers discover how to find the missing angle of a triangle. Then, they practice identifying triangles, find missing angles, and find missing side lengths of...
Digging Into Math
Classifying Triangles
Young mathematicians explore the world of three-sided shapes in this activity on the different types of triangles. Starting with a general introduction to classification using Venn diagrams, children learn how to...
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 plan, they will create triangles on their calculators using the Cabri Jr. application. They then identify three...
Curated OER
Geometric Figures-Triangles
Fourth graders explore triangles. In this math lesson, 4th graders discuss the different types of triangles. Students create triangles using wiki sticks. Students complete an online matching game.
K-5 Math Teaching Resources
2-D Shape Cards
Add some visual support to your elementary geometry lessons with this set of printable shape cards. From triangles and squares to octagons and nanogons, this simple resource can be used in countless ways to develop children's knowledge...
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, young scholars follow step by step directions to create triangles on their calculator. They identify the type...
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
Exterior and Interior Angles of Triangles
Tenth graders explore the exterior and interior angles of triangles. They use a theorem in order to prove a theorem about all polygons. Students use the theorem and its applications to find the angles of different types of triangles.
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
Scalene Triangles
Fifth graders identify and classify scalene, equilateral, and isosceles triangles. In this triangle instructional activity, 5th graders define the different attributes of 3 types of triangles and sort them by descriptions and...
Houghton Mifflin Harcourt
Unit 5 Math Vocabulary Cards (Grade 6)
Acute angle, line of symmetry, and vertex are a few terms you'll find in a set of 90 flashcards designed to reinforce math vocabulary. Included in the set are two types of cards; a word card printed in bold font, and a...
Houghton Mifflin Harcourt
Unit 3 Math Vocabulary Cards (Grade 1)
Reinforce math vocabulary with a set of flashcards. Each card showcases a boldly typed word or a picture representation with labels. The topics are geometry related and include terms such as cones, faces, pyramids, sides, and...
Exploratorium
The Four-Square Quilt
Youngsters recognize that triangles can be combined together to make various shapes. The learning activity provides a series of seven steps that engage children in applying transformations to triangles. Pupils use a quilt template and...
Curated OER
Basic Right Triangles
Elementary schoolers examine the attributes of triangles. In this triangle lesson, learners compare regular triangles and right triangles. They explore vertices and angles and investigate obtuse and acute angles. Pupils draw multiple...
Curated OER
Algebra/Geometry Institute Summer 2009 - Triangles and the Pythagorean Theorem
Seventh graders find the perimeter and area of triangles. For this finding the perimeter and area of triangles lesson, 7th graders find the perimeter and area of triangles given two sides. Students find the missing side by...
Curated OER
Investigation Area of Geometric Shapes
Fourth graders use triangle paper to design patterns using geometric figures and find the areas of those figures by counting units. Students are assessed by determining which figure has the greatest area and explaining their reasoning.
Curated OER
Constructing Midsegments of Triangles
Students construct midsegments. In this geometry lesson, students make conjectures and apply properties of triangles to solve problems. They complete an activity on the computer.
Curated OER
Shape Up
Students explore differents types of triangles and quadriaterals. In this polygon lesson, students model identify and compare two and three dimensional geometric figures. Students create tangrams and discover the difference between...
Curated OER
Ratios of Similar Figures
Students identify the ratios of different triangles. In this geometry instructional activity, students identify the similarity and differences of triangles. They use the navigator to move the sides of the triangle around.
Curated OER
Congruent Triangles
Learners identify properties of triangles. In this geometry instructional activity, students differentiate between similar and congruent triangles. They use the umber of sides to help define the angle of the polygon.
Curated OER
Ratios in Right Triangles
Learners calculate the sides of right triangles in this trigonometric ratios instructional activity. They use Cabri Jr. software and TI-83 or TI-84 calculators to find the side lengths and their ratios to each other for various...
Curated OER
Triangle Congruence
Students use web applet to create congruent triangles. For this geometry lesson, students differentiate between congruent and similar. They create shapes online and drag those shapes around to create visuals of triangles.
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...