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...
Digging Into Math
Classifying Triangles
Young mathematicians explore the world of three-sided shapes in this instructional activity on the different types of triangles. Starting with a general introduction to classification using Venn diagrams, children learn how to...
CK-12 Foundation
Pythagorean Theorem to Classify Triangles: Missing Angles
Learn to use the Pythagorean Theorem with non-right triangles. Pupils use the interactive to discover the relationship between the lengths of sides for acute and obtuse triangles. They compare the squares of the sides of the triangles to...
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...
Curated OER
Acute Triangles
Learners study acute triangles. They measure angles using a protractor, then classify the triangles as either right, obtuse, or acute. Everyone creates a design for a Navajo rug using only acute triangles.
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
What are the Kinds of Triangles?
Fifth graders classify triangles. In this triangle lesson, 5th graders learn about the characteristics that make up a triangle. They are instructed through video, PowerPoint slides, and teacher-led demonstrations.
Curated OER
Right Triangles
Learners classify triangles and make connections regarding angle measurements and attributes of acute, right, and obtuse triangles. They listen to teacher define and explain triangles. Everyone imagines a place where a broken wing for a...
Curated OER
Triangle Inequality Theorems Investigation
Students estimate and measure triangles. In this geometry lesson, students identify the relationship between three sides and a triangle. They use the inequality theorem to decide if a triangle will be formed or not.
Mt. San Antonio Collage
Isosceles Triangles and Special Line Segments
Under which conditions can a triangle be classified as isosceles? High schoolers practice identifying isosceles triangles and special line segments, including angle bisectors, medians of triangles, and perpendicular bisectors of sides of...
Curated OER
Branding Circles, Squares, Rectangles, Triangles
Compare and classify 2-D shapes! Kindergarteners inspect the attributes of plane shapes and examine shapes in everyday life. They label the circles, squares, rectangles, and triangles they find. This is the website where you can find the...
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
Angles, Triangles, Quadrilaterals, Circles and Related
Students classify angles. In this angles lesson plan, students explore the characteristics of angles, triangles, quadrilaterals and circles. They identify polygons and sing a classifying angles song. Students participate in a...
Curated OER
How many isosceles Triangles Can You Find?
Fifth graders solve problems while examining a variety of isosceles triangles. For this isosceles triangle lesson, 5th graders examine shapes to find their characteristics. Students pay particular attention to the...
Math Mammoth
Triangles 1
For this triangles worksheet, learners measure and calculate the measurements of eight triangles, their sums and classify the triangles as acute, obtuse or right.
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...
Curated OER
Isosceles Triangles
Students investigate triangles. In this shapes geometry lesson, students define and state the attributes for equilateral, scalene, and isosceles triangles. Students locate the prefix "tri" in a variety of words and make connections with...
Curated OER
Types of Triangles
Fifth graders explore the required functions of the Geometer's Sketchpad. Using the computer software, they construct similar triangles and identify them by angles and sides. Students classify triangles. Afterward, they complete problems...
Curated OER
Geometric Shapes
Students identify polygons. In this geometric shape instructional activity, students explore the characteristics of polygons. They identify polygons, and classify triangles according to their sides and angles. Students...
Curated OER
Triangle Inequality Theorem
Learners use the inequality theorem to solve triangles and their properties. In this geometry instructional activity, students are given spaghetti of different lengths and asked to create triangles. They conclude the necessary length...
Curated OER
Review of Triangles
Learners investigate the Pythagorean Theorem. In this geometry instructional activity, students define angles and sides of right triangles. They calculate the area and surface area using formulas derived by the Pythagorean Theorem.
Curated OER
Scalene Triangles
Fifth graders identify and classify scalene, equilateral, and isosceles triangles. In this triangle lesson, 5th graders define the different attributes of 3 types of triangles and sort them by descriptions and...
Curated OER
Classifying Polygons
Students study polygons. In this math instructional activity, students play a game in which they learn the classification system for polygons. Students identify the properties of quadrilaterals.
Curated OER
Roundup Shapes
Shapes are all around us! Kindergartenrs identify shapes in their world and guess the shape being described. They participate in a shape hunt.