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Instructional Video1:25
Brian McLogan

Find the missing measure of angles for an isosceles triangle

12th - Higher Ed
👉 Learn how to find the missing side of a triangle. A triangle is a polygon with three sides. Triangles are classified on the basis of the angles or on the basis of the sides. The classification of a triangle on the basis of the sides...
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Instructional Video2:35
Brian McLogan

Using the Isosceles triangle theorem to find the measure of x

12th - Higher Ed
👉 Learn how to find the missing side of a triangle. A triangle is a polygon with three sides. Triangles are classified on the basis of the angles or on the basis of the sides. The classification of a triangle on the basis of the sides...
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Instructional Video0:51
Brian McLogan

What is a scalene triangle

12th - Higher Ed
👉 Learn the essential definitions of triangles. A triangle is a polygon with three sides. Triangles are classified on the basis of their angles or on the basis of their side lengths. The classification of triangles on the bases of their...
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Instructional Video1:41
Brian McLogan

How to determine all of the measure of angles for an equilateral triangle

12th - Higher Ed
👉 Learn how to find the missing side of a triangle. A triangle is a polygon with three sides. Triangles are classified on the basis of the angles or on the basis of the sides. The classification of a triangle on the basis of the sides...
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Instructional Video10:03
Cerebellum

Geometry - Proofs continued

9th - 12th
Understand and making sense of geometry: Proofs continued. This is part 3 from the series 'Geometry Program'.
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Instructional Video5:23
Brian McLogan

Using a Two Column Proof to Prove Two Sides of a Triangle are Equal

12th - Higher Ed
👉 Learn how to prove that two triangles are congruent. Two or more triangles are said to be congruent if they have the same shape and size. There are many postulates and theorems to determine whether two triangles are congruent. They...
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Instructional Video5:26
Curated Video

GCSE Secondary Maths Age 13-17 - Geometry & Measures: Proof - Congruent Triangles - Explained

9th - 12th
SchoolOnline's Secondary Maths videos are brilliant, bite-size tutorial videos delivered by examiners. Ideal for ages 13-17, they cover every key topic and sub topic covered in GCSE Maths in clear and easy to follow steps. This video...
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Instructional Video6:57
Brian McLogan

What is the Triangle Inequality Theorem - Congruent Triangles

12th - Higher Ed
👉 Learn about congruent triangles theorems. Two or more triangles are said to be congruent if they have the same shape and size. There are many methods to determine whether two triangles are congruent. Some of the methods include: (1)...
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Instructional Video18:12
3Blue1Brown

How to lie using visual proofs

12th - Higher Ed
Time stamps: 0:00 - Fake sphere proof 1:39 - Fake pi = 4 proof 5:16 - Fake proof that all triangles are isosceles 9:54 - Sphere "proof" explanation 15:09 - pi = 4 "proof" explanation 16:57 - Triangle "proof" explanation and conclusion
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Instructional Video2:57
Curated Video

Area Of A Triangle 1/2absinC

12th - Higher Ed
The area of a triangle is ½ the base X perpendicular height. If we don’t have the perpendicular height, there is another formula we can use: 1/2absinC which we look at in this video. We need two sides and the angle in between. This will...
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Instructional Video11:01
Cerebellum

Geometry - Definitions

9th - 12th
Understand and making sense of geometry: Triangles, and their angles. This is part 1 from the series 'Geometry Program'.
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Instructional Video2:57
Curated Video

Area Of A Triangle 1/2absinC | Trigonometry | Maths | FuseSchool

12th - Higher Ed
The area of a triangle is ½ the base X perpendicular height. If we don’t have the perpendicular height, there is another formula we can use: 1/2absinC which we look at in this video. We need two sides and the angle in between. This will...
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Instructional Video3:02
CK-12 Foundation

Isosceles Triangles: Lesson

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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Worksheet
Mt. San Antonio Collage

Isosceles Triangles and Special Line Segments

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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Instructional Video3:02
CK-12 Foundation

Equilateral Triangles: Lesson

8th - 11th Standards
Take a second look at triangles that are equal all the way around. The video reminds viewers what an equilateral triangle is and points out that the three angles are the same. Using the fact that equilateral triangles are also isosceles,...
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Activity
Illustrative Mathematics

Reflections and Isosceles Triangles

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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Worksheet
Curated OER

Proofs

8th - 11th
In this geometric proof worksheet, students compose 20 triangle congruency proofs. Students will decide if there is enough information in problems 1-6 to prove if any triangles are congruent. In problems 17 to 20, students use given...
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Assessment
Inside Mathematics

Circles in Triangles

9th - 12th Standards
Challenge the class with inscribed circles in triangles. The assessment task requests class members use their knowledge of circles and right triangles to prove two triangles are congruent. They go on to utilize their knowledge of...
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Worksheet
Curated OER

Triangle worksheets

10th
In this geometry worksheet, 10th graders explore triangle properties, including the sum of the measures of the angles of a triangle, the triangle inequalities, properties of isosceles triangles, properties of congruent triangles, and...
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Worksheet
Geometry Accelerated

Accelerated Geometry Review Sheet

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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Worksheet
Curated OER

Triangle Proofs

9th - 12th
In this triangle proofs worksheet, students answer 5 questions about triangles and polygons given certain information. Students then construct 4 triangle or polygon proofs.
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Worksheet
Curated OER

Triangles and Congruence

8th - 10th
Can your class construct triangles and determine congruence? Find out with this well put together activity. THey construct triangles to given specifications and identify if they are congruent. There are 3 muti-step problems to solve.
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Handout
Mt. San Antonio Collage

Congruent Triangles Applications

9th - 12th Standards
Triangles are all about threes, and practicing proving postulates is a great way to get started. The first page of the activity provides a brief introduction of the different properties and postulates. The remaining pages contain...
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Worksheet
Curated OER

Coordinate Geometry Proofs

10th
In this coordinate geometry worksheet, 10th graders solve and draw 10 different problems related to complete proofs in coordinate geometry. First, they prove that a figure with given points is another figure by using slopes. Then,...