Math Mammoth
Triangles
A six-page packet walks, or bends learners through angles that combine to create triangles. Definitions are given for right triangles, obtuse and acute triangles. They draw angles according to directions, using a protractor to meet the...
Math Mammoth
Circles
Your class examines a series of shapes and discusses how we know that they are not circles. In this way, you begin to acquaint them with the properties and parts of this geometric figure. Then, teach them how to use a protractor to...
Curated OER
Minimum and Maximum Perimeter
Pupils practice a variety of strategies with varying numbers of tiles to form shapes and then find the minimum and maximum perimeter for each one. Each group is assigned a different area to build either with square tiles or a geoboard....
Alabama Learning Exchange
Is It a Triangle?
Learners explore the concept of triangle inequalities. In this triangle inequality lesson, students cut spaghetti noodles into given lengths. Learners use the noodles to complete a worksheet about triangle inequalities. ...
Alabama Learning Exchange
Trapezoids: What's Equal or Right About Them?
Pupils explore the concept of trapezoids. In this trapezoids instructional activity, students identify legs and bases of a trapezoid. Pupils discuss the similarities and differences between isosceles trapezoids and right...
Government of Alberta
Learn Alberta: Math Interactives: Exploring and Solving Triangles
This multimedia Learn Alberta math resource focuses on the many triangles that are found in our everyday environment. The accompanying interactive component asks students to find triangles in a picture and to solve for the missing angles...
Beacon Learning Center
Beacon Learning Center: Triangles Side by Side
This comprehensive web lesson describes how to classify triangles by their angle and side measurements. It provides real-world examples and exercises for students to practice the skill.
That Quiz
That Quiz: Practice Test: Triangles
Test your knowledge on the attributes of triangles. There are eleven levels that may be completed with or without a timer.
Oswego City School District
Regents Exam Prep Center: Angles and Triangles
On this site a viewer can learn about the different types of triangles, and categorized by either angles or sides. Tutorials are also included for interior and exterior angles of triangles. A teacher resource page includes a lesson plan...
Cuemath
Cuemath: Midsegment of a Triangle
This mini-lesson explores the world of the midsegment of a triangle by finding the answers to questions like what is midsegment of a triangle, triangle midsegment theorem, and proof with the help of interactive questions.
Cuemath
Cuemath: Acute Triangle
Explore the world of acute triangles in this mini-lesson. Explores its properties, how to create it, and other interesting facts related to acute triangles.
Cuemath
Cuemath: Altitude of a Triangle
Explore the world of the altitude of a triangle in this mini-lesson including its definition, altitudes in different types of triangles, formulae, some solved examples, and a few interactive questions for you to test your understanding.
Houghton Mifflin Harcourt
Holt, Rinehart and Winston: Homework Help Independent Practice: Triangles
Get independent practice working with triangles. Each incorrect response gets a text box explanation and another try. Correct responses are confirmed.
Rice University
Rice University: Geometry Online: Impossible Triangles
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.
Shodor Education Foundation
Shodor Interactivate: Triangle Explorer
Students explore the nature of triangles and their area. An applet and instructor resources are included. [Requires Java.]
Texas Instruments
Texas Instruments: Dynamic Geometry: Basic Constructions
Students use the Cabri Jr. application to draw triangles and construct perpendicular bisectors on the sides of a triangles. They study the properties of a triangle and understand how the measures of angles of a triangle is always 180...
SEDL
The Timss Mathematics Segment: Geometry
This site explores the area of congruent triangles and how it is a difficult area to understand.
Homeschool Math
Homeschool Math: Triangles
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.
Texas Instruments
Texas Instruments: Surround and Be Found! Triangular Areas, That Is!
In this activity, students use the Geoboard to determine the area of triangles using the surrounding rectangle technique. They also develop and use formulas to determine the area of triangles. [Requires Adobe Reader.]
Texas Instruments
Texas Instruments: Try Angle?
In this activity, students investigate properties of triangles by randomly generating possible side lengths for triangles. They learn to determine if three line segments can form a triangle. They also learn to classify triangles as...
McGraw Hill
Glencoe Mathematics: Online Study Tools: Triangles and Angles
This site gives a short interactive quiz which allows students to self-assess their understanding of the concept of triangles and angles.
Mangahigh
Mangahigh: Shape: The Angles Inside a Triangle
Test your knowledge of the missing angle measure.
Mangahigh
Mangahigh: Shape: Types of Triangle
Test your knowledge of triangles by identifying the different types.
Mangahigh
Mangahigh: Shape: Proof of the Sum of the Angles in a Triangle
Determine that all angles in a triangle equal 180 degrees.