Triangle Teacher Resources

Find Triangle educational ideas and activities

Showing 1 - 20 of 8,264 resources
Show your school spirit while proving theorems about triangles! Your student geometers are charged with coming up with a new design for the school pennant, following specific guidelines. Along the way, they need to prove the theorem that base angles of an isosceles triangle are congruent. Not only is this a learning activity, if you allow time to decorate the pennants, you'll end up with great room or hall decorations. 
As the fourth part of a series on the Pythagorean Theorem, Sal continues an exploration of the ways to calculate the length of sides of a right triangle using algebra. He also explores using this theorem to solve problems involving a right triangle with 30 degree and 60 degree angles.
Although a rather complicated topic, this video manages to clearly explain the concept of solving problems involving similar triangles. It employs problem solving to determine whether two figures are similar triangles. In addition, it provides guidance for finding the anglesÕ values. Tip: the presentation finishes prior to solving the final problem. Furthermore, this is the first part of a series on similar triangles.
Delving into basic trigonometry, this resource shows how to find the area of an inscribed equilateral triangle. Using a high-level problem, HeronÕs theorem is used to find the area of a figure. Prior to SAT testing, use this as a review.
The process for calculating values using a right triangle with angles of 45 degrees is covered in this third portion of the Pythagorean Theorem series. Here, Sal uses algebra to calculate the value of an angle. The solution to the sample problems involves a complicated resolution. As a result, it would be helpful in preparing for the SAT.
Finding the area of each of the triangles that are created by drawing two diagonal lines through a rectangle is explored in this lecture. It provides a detailed explanation of how to use a formula to solve the given problem. Tip: Use this for test preparation purposes.
Using this video, which is the fourth in a series, the instructor continues a discussion involving the Pythagorean theorem. This video focuses on calculations involving right triangles with 30 and 60 degree angles.
What else does physical health include besides exercise and nutrition? How can I support my mental health? Does social health just refer to relationships with friends? How are all of these questions vital to the body's overall efficiency and well being? Discover the primary components of each of the three major areas (physical, social, and mental health) of the health triangle, and discuss what factors can affect and risk one's journey toward lifelong wellness.
Most high schoolers are very familiar with the area of the triangle being equal to 1/2 base times the height. Here, they will develop and test their formula for the area of a triangle when given two adjacent sides and the included angle. After they develop their formula, they will use a dynamic geometry software system, such as Geometer's Sketchpad or GeoGebra to test their conjecture. 
Here the focus is on triangle congruence. Through an activity that requires investigation, questioning, and working together, geometers learn to identify corresponding parts of triangles to determine if the triangles are congruent. Triangles are transformed through reflection, rotation, and translation. 
This is an interesting geometry problem. Given the figure, find the area of a triangle that is created by the intersecting lines. The solution requires one to use what he/she knows about coordinate geometry, as well as triangle and angle congruence, rigid motion, rotation, translation, and the distance formula. Challenge your learners to find the solution two different ways. 
Explore, investigate, and finally prove the angles in a triangle have a sum of 180 degrees. Young geometers use the Interior Angles Theorem, and properties and definitions of congruency. 
This is an excellent lesson plan for exploring the criteria for triangle congruence. After a review of the definition of congruent triangles, high schoolers work in small groups to rotate through six stations. At each station, they are given three measurements and must determine if the measurements will always produce congruent triangles. Geometers use paper and pencils, patty paper, rulers, and protractors to conduct their investigations. They note their findings on a recording sheet and make conjectures about their results. The activity should give learners a good understanding of SSS, SAS, ASA, and AAS, as well as discounting AAA and SSA as criteria for triangle congruence. Depending on the length of class periods, the lesson plan may require more than one day to complete.
Learners discover a method for determining the slope of a line by creating and comparing similar triangles. They fold coordinate grids to make three similar triangles then measure the sides to compare the relationships between the triangles. The slope equation or rise over run is developed from these relationships.
The problem seems simple: find the area of the equilateral triangle whose sides are each length 1. In fact, this same problem is solved in 8th grade, addressing a different Common Core standard, using the formula for area of a triangle to solve. Here the objective is to get geometry learners develop an understanding of two new solutions. One using congruent triangles, and the other using trigonometric ratios. 
Geometers explore symmetries of isosceles triangles by using rigid transformations of the plane. They complete four tasks, including congruence proofs, which illustrate the relationship between congruence and rigid transformations. The activity requires a thorough understanding of the definition of reflection about a line and is better suited for more sophisticated geometry students.
A detailed lesson plan that has learners investigating the criteria necessary for triangle congruence. Working in groups, they visit six different stations. At each station they are given three measurements and are asked to determine if the measurements will always produce congruent triangles. After visiting all six stations, students discuss their findings and generalize the results into SSS, SAS, ASA, and AAS.
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 relate the area of the square to the right triangles? Then they use the webpage, which provides different triangles on a coordinate grid to calculate the the area. The lesson discusses right triangles, while medium and hard levels of the activity have non-right triangle examples. Learners should be able to find the area of a triangle when height or base is not obvious using the distance formula or box method if using the hard level examples. 
Looking for a nice activity that will help deepen your geometry learners' understanding of similar triangles? This activity maps a number of triangles embedded in a square on dot graph paper. Young geometers need to find as many different similar triangle pairs as they can find and justify their solutions. 
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 introduction to classifying triangles based on their side lengths.