Lesson Plan
Curated OER

Geometry Journal: Isosceles Triangles

For Teachers 10th - 12th
In this isosceles triangles worksheet, students justify and determine the symmetry of an isosceles triangle. They explore the bisector of rectangles. This three-page worksheet contains two problems. Answers are listed on page three.
Lesson Plan
Illustrative Mathematics

Lines of Symmetry for Triangles

For Teachers 3rd - 5th Standards
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...
Lesson Plan
Curated OER

Toothpick Triangles

For Teachers 4th - 8th
Students draw a chart (included in the lesson) to use with their investigation. They review terminology of triangles and receive toothpicks to use in the lesson. Beginning with three toothpicks, students form a triangle. They complete...
Lesson Plan
Curated OER

Study Buddies: Classifying Triangles

For Teachers 4th - 5th
In this math worksheet, learners analyze an informative chart about the measurement and angles of equilateral, isosceles and scalene triangles. Students then answer 5 questions about classifying triangles.
Lesson Plan
Alabama Learning Exchange

What You Know About the Bermuda Triangle?

For Teachers 9th - 12th Standards
Get lost in the classifications. Using the backdrop of the Bermuda Triangle, pupils classify it by angle and side measures. They also learn information about the triangle and its history.
Lesson Plan
Curated OER

Geometric Figures-Triangles

For Teachers 4th
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.
Lesson Plan
Curated OER

Isosceles Triangles

For Teachers K - 2nd
Learners investigate triangles. In this shapes geometry lesson, students define and state the attributes for equilateral, scalene, and isosceles triangles. Learners locate the prefix "tri" in a variety of words and make connections with...
Lesson Plan
Virginia Department of Education

How Many Triangles?

For Teachers 9th - 11th Standards
Something for young mathematicians to remember: the sum of any two sides must be greater than the third. Class members investigates the Triangle Inequality Theorem to find the relationship between the sides of a triangle. At the...
Lesson Plan
Texas Instruments

Identifying a Triangle by its Sides and Angles

For Teachers 9th - 12th Standards
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,...
Lesson Plan
National Security Agency

Classifying Triangles

For Teachers 4th - 8th Standards
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...
Lesson Plan
Curated OER

Types of Triangles

For Teachers 1st - 2nd
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.
Lesson Plan
Curated OER

Triangle Foldable

For Teachers 4th - 5th
In this math worksheet, students cut out six cards with the names of different triangles. Triangles include equilateral, scalene, and isosceles.
Lesson Plan
Curated OER

Identify triangles

For Teachers 9th - 10th
Students explore triangles. In this geometry activity, students will create note cards with pictorial depictions of right, acute,obtuse, scalene, isosceles, equilateral and equiangular triangles. Students will verbally describe each type...
Lesson Plan
Curated OER

Identifying Triangles

For Teachers 6th
Sixth graders identify and define a variety of triangles. For this identification of triangles lesson, 6th graders draw examples of each triangle on a whiteboard, then complete a worksheet.
Lesson Plan
Curated OER

Exploring Triangles

For Teachers 1st - 12th
Students research the different types of triangles, including right, isosceles, scalene, and equilateral triangles. They identify the characteristics of various types of triangles and then draw them using appropriate vocabulary to...
Lesson Plan
Curated OER

Triangles

For Teachers 5th - 6th
Young scholars 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...
Lesson Plan
Curated OER

Triangles

For Teachers 5th - 6th
Students draw triangles. In this shapes lesson, students discuss what they already know about triangles, what they are and what they are made up of. Students discuss the types of triangles and practice drawing each type.
Lesson Plan
Curated OER

Triangles

For Teachers 6th - 10th
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...
Lesson Plan
Curated OER

Angles, Triangles, Quadrilaterals, Circles and Related

For Teachers 6th - 8th
Students classify angles. For this angles lesson, students explore the characteristics of angles, triangles, quadrilaterals and circles. They identify polygons and sing a classifying angles song. Students participate in a manipulative...
Lesson Plan
Curated OER

The Truth About Triangles And Proofs

For Teachers 9th - 12th
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...
Lesson Plan
Willow Tree

Common Geometric Figures

For Students 8th - 11th Standards
Geometry could be called the study of figures. An overview of the figures found in a typical geometry course contains a study of different triangles, quadrilaterals, and regular polygons. 
Lesson Plan
Curated OER

Triangle Inequality Theorem

For Teachers 8th - 10th
Young scholars 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...
Lesson Plan
Curated OER

Scalene Triangles

For Teachers 5th
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...
Lesson Plan
Curated OER

The Greedy Triangle-Intro to Geometric Shapes

For Teachers 4th - 6th Standards
 In this geometry lesson, learners read The Greedy Triangle and use geoboards to construct geometric shapes. They identify the number of sides and angles each shape has.