Isosceles Triangle Teacher Resources

Find Isosceles Triangle lesson plans and worksheets
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Isosceles Triangles: Lesson

For Students 8th - 11th Standards
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.
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Isosceles Triangles on a Geoboard

For Students 6th - 7th Standards
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.
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Lesson Planet

Pythagoras Rectangles and Isosceles Triangles

For Students 7th - 12th Standards
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...
EngageNY

Base Angles of Isosceles Triangles

For Students 9th - 10th Standards
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...
Lesson Planet

Isosceles Triangles and Special Line Segments

For Students 9th - 12th Standards
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...
7:11
Lesson Planet

The Isosceles Triangle Theorem is Actually Really Simple!

For Students 9th - 12th Standards
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. 
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Isosceles Triangle Proof

For Students 9th - 12th Standards
Isosceles means two sides are congruent. Given an isosceles triangles, pupils develop a geometric proof showing that the two base angles are congruent. 
9:54
Lesson Planet

SAT Prep: Test 1 Section 9 Part 3

For Students 9th - 12th
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...
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Isosceles Triangles

For Students 10th
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...
Lesson Planet

Isosceles Triangles

For Teachers 4th - 5th
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...
Lesson Planet

Theorems of Triangles

For Teachers 9th - 11th Standards
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...
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Lesson Planet

How Do You Find Missing Angles in an Isosceles Triangle?

For Teachers 6th - 8th
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...
Lesson Planet

Geometry Journal: Isosceles Triangles

For Teachers 10th - 12th
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.
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Lesson Planet

How Do You Find Missing Angles in an Isosceles Triangle Using Right Triangles?

For Teachers 6th - 8th
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...
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Isosceles Triangle Theorem

For Teachers 8th - 10th
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.
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Reflections and Isosceles Triangles

For Teachers 9th - 11th Standards
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...
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Isosceles Triangle Spaces

For Students 7th - 10th Standards
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,...
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Sea Squares

For Teachers 10th
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...
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Lesson Planet

Pennant Pride

For Teachers 9th - 11th Standards
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...
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How many isosceles Triangles Can You Find?

For Teachers 5th
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...
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Geometry Regents Questions: Isosceles Triangle Theorem

For Teachers 9th - 12th
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.
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How many isosceles triangles can you find?

For Teachers 7th
Seventh graders recognize the characteristics of isosceles triangles. In this isosceles triangle lesson plan, 7th graders use geoboards to create isosceles triangles. Students record results and explain why they have an isosceles triangle.
Lesson Planet

Isosceles Triangles

For Students 9th - 12th
In this geometry worksheet, high schoolers 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. 
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Lesson Planet

Draw Triangles Using Given Angles

For Students 6th - 8th Standards
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. 

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