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
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Illustrative Mathematics

Right Triangles Inscribed in Circles II

For Teachers 9th - 10th Standards
So many times the characteristics of triangles are presented as a vocabulary-type of lesson plan, but in this activity they are key to unraveling a proof. A unique attack on proving that an inscribed angle that subtends a diameter must...
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.
Activity
Teach Engineering

Stay in Shape

For Teachers 7th - 9th Standards
Using their knowledge of right triangles, pupils find out how far a ship is from a light house. Class members determine how far around the world a ship would be sailing at a constant speed.
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...
Activity
Exploratorium

The Four-Square Quilt

For Teachers K - 2nd
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...
Activity
Under the Dome

Triangle Mystery ...

For Students 6th Standards
Build a pyramid based on sums. Individuals watch a video of a computer program that creates a pyramid of numbers based upon a starting number. The scholars develop a hypothesis on how the number trick works and share their thoughts on...
Lesson Plan
Curated OER

Symmetries of a Quadrilateral I

For Teachers 9th - 10th Standards
Learners examine the properties of quadrilaterals from the point of view of rigid motion. Different types of quadrilaterals are characterized by their symmetries, so learners explore the symmetries of a described quadrilateral to...
Activity
PBS

Terrific Trees

For Teachers 3rd - 8th
Engage in a shady activity to practice measurement techniques. Classes venture outside to collect measurements of various trees, using different strategies to measure the height, trunk circumference, width, and crown size. Then they...
Lesson Plan
Curated OER

Shapes and Their Insides

For Teachers 2nd - 4th Standards
Learners follow a series of instructions for drawing and coloring different shapes in order to learn the difference between the perimeter and area of a polygon. Then they are asked to find the perimeter and area of a 3x4 rectangular...
Activity
Teach Engineering

Straw Bridges

For Teachers 6th - 8th
Pairs work as engineering teams to design and build model bridges from drinking straws and tape. In this third segment in a series of 10, teams compete in an attempt to build the strongest bridge. To help with the design, the groups...
Lesson Plan
Curated OER

Symmetries of a Quadrilateral II

For Teachers 9th - 10th Standards
Learners investigate the symmetries of a convex quadrilateral in a collaborative activity. Rigid motion and complements are explored as learners analyze different cases of reflections across a line.
Lesson Plan
Illustrative Mathematics

Introduction to Linear Functions

For Teachers 7th - 9th Standards
Introduce your algebra learners to linear and quadratic functions. Learners compare the differences and relate them back to the equations and graphs. Lead your class to discussions on the properties of a function or a constant slope...
Lesson Plan
Illustrative Mathematics

Sort and Count

For Teachers Pre-K - 1st Standards
Young mathematicians are on their feet and moving around in this primary grade sorting activity. After giving each child an object or picture card, they then sort themselves into groups, counting to see which has the most or least...
Lesson Plan
Illustrative Mathematics

Make Your Own Puzzle

For Teachers K - 2nd Standards
Puzzling over what geometry lesson to teach next? Look no further. This simple activity teaches young mathematicians how shapes can be decomposed into smaller figures, and how smaller figures can be assembled into larger shapes. To learn...
Activity
Beauty and Joy of Computing

Sprite Drawing and Interaction

For Students 8th - 12th
Discover how to program objects to move on a screen. In the second lab of a five-part unit, each learner uses block instructions to program a sprite to follow their mouse (cursor). They investigate how to use these same block...
Activity
AAA Math

Aaa Math: Types of Triangles Based on Angles

For Students 3rd - 5th Standards
Students can practice classifying triangles based on angle measurements through a series of self-check exercises and timed learning games.
Activity
AAA Math

Aaa Math: Types of Triangles Based on Sides

For Students 3rd - 5th Standards
Students can practice classifying triangles based on side lengths through a series of self-check exercises and timed learning games.
Activity
Varsity Tutors

Varsity Tutors: Hotmath: Practice Problems: Congruent Triangles and Triangle Relationships

For Students 9th - 10th Standards
Twenty-four problems cover the topics of congruent triangles and triangle relationships in various settings. They are given with each step to the solution cleverly revealed one at a time. You can work each step of the problem then click...
Activity
Homeschool Math

Homeschool Math: Triangles

For Students 3rd - 8th Standards
This lesson plan provides students with an opportunity to practice drawing and measuring triangles and angles. It also shows pictures and gives definitions of each type of angle and triangle.
Activity
K-5 Math Teaching Resources

K 5 Math Teaching Resources: Isosceles Triangles on the Geoboard [Pdf]

For Students 3rd - 5th Standards
Students will learn about isosceles triangles. Materials needed include circular geoboards, rubber bands, circular geoboard paper and rulers.
Activity
Texas Instruments

Texas Instruments: Constructing Triangles

For Teachers 9th - 10th Standards
This activity focuses on the various ways to construct the different types of triangles such as isosceles, equilateral, right, and right isosceles triangles. Students will begin by constructing triangles based on a minimal definition of...
Activity
Rice University

Rice University: Geometry Online: Impossible Triangles

For Students 9th - 10th Standards
This site has an activity that displays several impossible triangles. The rules for triangles are also displayed. The student has to determine which rule has been violated for each impossible triangle.

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