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Lesson Plan
Curated OER

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 Plan
Curated OER

Isosceles Triangle Theorem

For Teachers 8th - 10th
For this geometry worksheet, learners 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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Lesson Plan
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...
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Worksheet
Mt. San Antonio Collage

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...
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Lesson Plan
Curated OER

Geometry of Triangles - Week 6

For Teachers 10th - 12th
In this triangle worksheet, students explore the characteristics of triangles. They find the area of a pentagon, lengths of the sides of a triangle and the area of a quadrilateral. This two-page worksheet contains seven problems.
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Lesson Plan
Curated OER

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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Assessment
Concord Consortium

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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Worksheet
Curated OER

Isosceles Triangles

For Students 9th - 12th
For this geometry worksheet, students 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 Plan
Alabama Learning Exchange

What You Know About the Bermuda Triangle?

For Teachers 9th - 12th Standards
Get lost in the classifications. Using the backdrop of the Bermuda Triangle, pupils classify it by angle and side measures. They also learn information about the triangle and its history.
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Lesson Plan
2
2
Curated OER

Two Triangles' Area

For Teachers 7th - 9th Standards
Need an activity for teaching the Pythagorean Theorem? Geometry juniors apply the Pythagorean theorem to two triangles to determine a final calculation. 
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Lesson Plan
Curated OER

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 Plan
Curated OER

Isosceles Triangle Theorem

For Teachers 8th - 9th
In this geometry worksheet, students differentiate between isosceles and regular triangles. They calculate the area and perimeter of the triangle. There are eleven questions with an answer key.
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Lesson Plan
Curated OER

Isosceles Triangles

For Teachers 9th - 10th
Students identify the properties of an isosceles triangle. In this geometry lesson, students find the midpoint, median and angle bisector of a triangle. They construct angle bisectors and measure missing angles.
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Worksheet
Curated OER

The Isosceles Triangle Problem

For Students 10th
In this geometry worksheet, 10th graders solve a problem involving an isosceles triangle.  The problem appears to be deceptively easy, but instead requires the use of trigonometry to arrive at a correct solution.  The one page worksheet...
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Lesson Plan
Curated OER

Geometry of Triangles - Week 6

For Teachers 12th - Higher Ed
In this geometry of triangles worksheet, students find the length of sides, are, and angle measurement of inscribed triangles, pentagons, and midpoint of a line. This two-page worksheet contains seven problems.
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Interactive
CK-12 Foundation

Lengths of Sides in Isosceles Right Triangles: Paper Football

For Students 9th - 12th Standards
Fuse sports and geometry by having your class create paper footballs—that are actually isosceles right triangles! Scholars use an interactive to create an isosceles right triangle to model a paper football. From the information in the...
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Lesson Plan
Virginia Department of Education

How Many Triangles?

For Teachers 9th - 11th Standards
Something for young mathematicians to remember: the sum of any two sides must be greater than the third. Class members investigates the Triangle Inequality Theorem to find the relationship between the sides of a triangle. At the same...
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Worksheet
Curated OER

Triangles

For Students 10th
In this triangles worksheet, 10th graders solve 12 different problems that include various angles of triangles. First, they determine the measure of an exterior angle. Then, students determine the measure of any of the base angles of an...
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Activity
Illustrative Mathematics

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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Lesson Plan
Curated OER

Constructions Triangles

For Teachers 10th Standards
Learners explore the difference between a construction and a drawing. They focus on various ways to construct different types of triangles. The activity is an application of Cabri Jr. and reinforces the difference between a constructions...
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Worksheet
Curated OER

Triangles

For Students 10th
In this triangles learning exercise, 10th graders solve and complete 22 different problems related to various types of triangles. First, they name the shortest and longest sides and the smallest and largest angles in each of triangles...
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Worksheet
Geometry Accelerated

Accelerated Geometry Review Sheet

For Students 8th - 10th Standards
Your geometry learners use their knowledge of various geometric concepts to write proofs. Starting with givens containing parallel line segments with transversals and triangles and quadrilaterals, and the mid-point and distance formulas;...
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Interactive
CK-12 Foundation

Special Triangle Ratios: Special Right Triangle Ratios

For Students 9th - 12th Standards
Go from one side length to any other side length with special right triangles. Individuals use the interactive to investigate the ratio of sides in 45-45 and 30-60 right triangles. Scholars make generalizations about the types of special...
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Worksheet
Curated OER

Perimetr of Isosceles Triangle

For Students 9th - 10th
For this geometry worksheet, learners calculate the perimeter of isosceles triangles given the sides of the triangles. There are 6 questions with an answer key.