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
Digging Into Math

Classifying Triangles

For Teachers 4th - 8th Standards
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...
Lesson Plan
Shodor Education Foundation

Triangle Area

For Teachers 6th - 9th Standards
While the lesson 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 they...
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

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

Exploring Triangles

For Teachers 1st - 12th
Young scholars 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

Constructions Triangles

For Teachers 10th Standards
Learners explore the difference between a construction and a drawing. They focus on various ways to construct different types of triangles. The lesson is an application of Cabri Jr. and reinforces the difference between a constructions...
Lesson Plan
Curated OER

SuperShapes, Part 1; "Tri"ing Triangles

For Teachers 5th - 6th
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...
Lesson Plan
Illustrative Mathematics

Alike or Different Game

For Teachers K Standards
How are a circle and triangle alike? How are they different? These are the types of questions children will answer while playing this fun geometry game. Including a variety of conventional and unconventional shapes, this activity allows...
Lesson Plan
Curated OER

Exploring Polygons and The Greedy Triangle

For Teachers 1st - 3rd
Excellent activity! Anne Linehane's geometry story, The Greedy Triangle, offers an opportunity to practice forming various types of polygons with your learners. Using elastic bands (or Chinese jump ropes),...
Lesson Plan
Curated OER

Triangles

For Teachers 5th - 6th
Students 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...
Lesson Plan
Curated OER

Shapes and Tools

For Teachers K - 1st
Young learners view different shapes drawn by the teacher on the board. The teacher identifies each shape by name and discusses the importance of knowing the difference between shapes when building something. The pupils complete the...
Lesson Plan
Curated OER

Similar and Congruent Triangles

For Teachers 2nd - 4th
Students create and classify different types of triangles using an online geo-board. They explore the concepts of similar and congruent as they discover how to draw similar and congruent triangles.
Lesson Plan
Curated OER

Exterior and Interior Angles of Triangles

For Teachers 10th
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.
Lesson Plan
Curated OER

Right Triangles

For Teachers 7th - 8th
In this right triangles worksheet, students solve and complete 2 different types of problems. First, they take the case of an isosceles right triangle with a given leg and hypotenuse. Then, students find the sum of the squares of the...
Lesson Plan
Curated OER

Shape Up

For Teachers 6th - 8th
Students explore differents types of triangles and quadriaterals. In this polygon lesson plan, students  model identify and compare two and three dimensional geometric figures. Students create tangrams and discover the difference...
Lesson Plan
Curated OER

Triangles

For Teachers 4th
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...
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

Triangle Congruence with Coordinate

For Teachers 7th - 9th Standards
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.
Lesson Plan
Curated OER

Types of Triangles

For Teachers 5th
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...
Lesson Plan
Curated OER

2-D polygons

For Teachers 3rd - 6th
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,...
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

Area Measures and Right Triangles

For Teachers 9th - 12th Standards
Your class will investigate the relationship among different triangles. This geometry lesson, demonstrates how to make a connection between triangles and the Pythagorean Theorem. They identify the missing side or angle of a triangle.