Isosceles Triangle Teacher Resources

Two sides give us two angles. A segment of a playlist on basic geometry revisits isosceles triangles. The presentation explains several properties and theorems related to isosceles triangles.

How many isosceles triangles can you create on a seven-by-seven peg board? This is the task scholars attack in their collaborative groups. The problem prompts discussion on distance, slope, and the definition of isosceles triangles.

When does the Pythagorean Theorem come in handy? An intriguing video uses the Pythagorean Theorem to solve problems other than simply finding the length of a side of a right triangle. Pupils find the diagonal of a rectangle and the...

Build confidence in proofs by proving a known property. Pupils explore two approaches to proving base angles of isosceles triangles are congruent: transformations and SAS. They then apply their understanding of the proof to more complex...

Under which conditions can a triangle be classified as isosceles? High schoolers practice identifying isosceles triangles and special line segments, including angle bisectors, medians of triangles, and perpendicular bisectors of sides of...

The isosceles triangle comes with its own set of properties. A lecturer shows how to apply the Isosceles Triangle Theorem to find missing side lengths or angle measures. The final example involves both square roots and quadratic equations. 

Isosceles means two sides are congruent. Given an isosceles triangles, pupils develop a geometric proof showing that the two base angles are congruent. 

If it takes a long time to complete the problems on the math SAT, it doesn't matter if they are correct - the problems that are left over will count against the student's score. Sal takes care to show quicker ways to complete problems...

In need of a fun way to define an isosceles triangle? This activity has learners fold a paper in half and then cut it to create an isosceles triangle. They determine the line of symmetry by folding the triangle in half and then use the...

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...

Finding the missing values of two angles in an isosceles triangle is not as difficult as it sounds. But how can two out of three angle's measurements be found? Well, there are special properties about an isosceles triangle which make...

Given an isosceles triangle, and the value of one angle, find the missing values. There are some special properties about isosceles triangles. Use the triangle sum theorem to solve this problem. Watch this video to see how the instructor...

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.

In this geometry worksheet, students differentiate between regular triangles and isosceles triangles. They apply the converse theorem and the vertex angle. There are eleven questions with an answer key.

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...

In this isosceles triangle worksheet, 10th graders solve and complete 8 different problems that include defining various isosceles triangles. First, they determine the midpoint of an illustrated triangle and then determine if each angle...

In this sea squares worksheet, 10th graders solve 5 different problems that include various geometrical figures. First, they draw a number line using one color. Then, students draw 2 obtuse angles and 3 isosceles triangles with different...

Your young designers use geometric concepts and isosceles triangle properties to create a blue print for a pennant with specific criteria. Second, they write a geometric proof outlining the correlation between base angle measures and the...

Fifth graders solve problems while examining a variety of isosceles triangles.  In this isosceles triangle lesson, 5th graders examine shapes to find their characteristics.  Students pay particular attention to the characteristics of...

Seventh graders recognize the characteristics of isosceles triangles. In this isosceles triangle instructional activity, 7th graders use geoboards to create isosceles triangles. Students record results and explain why they have an...

In this isosceles triangle worksheet, students solve 19 multiple choice and short answer problems.  Students use the isosceles triangle theorem to determine unknown angle measures.

How many different types of triangles can your class name? A discovery lesson guides learners through an exploration of the different triangle types and the relationships between their angles and sides. Using coordinate geometry,...

In this geometry worksheet, learners set up equations to solve for the missing angle or side of an isosceles triangle. All the equations turn out to be linear and not quadratic. There are 15 questions. 

Middle schoolers are given set angles and asked to draw a complete triangle by using a protractor. Watch how the narrator walks through each measure and line to finish with an isosceles triangle.