Curated OER
Altitudes and Orthocenters: Making Connections to the Nine-Point Circle
Students practice various equations for constructing nine-point circles for triangles.
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Triangles
Students identify triangles in the real world and construct their own triangle using drinking straws. They explore abstract triangles and find additional geometric shapes such as trapezoids. Students discuss similar shapes and examine...
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Right Triangles
Learners classify triangles and make connections regarding angle measurements and attributes of acute, right, and obtuse triangles. They listen to teacher define and explain triangles. Everyone imagines a place where a broken wing for a...
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Basic Right Triangles
Elementary schoolers examine the attributes of triangles. In this triangle lesson plan, learners compare regular triangles and right triangles. They explore vertices and angles and investigate obtuse and acute angles. Pupils draw...
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Classifying Triangles
This presentation shows how triangles are classified by angle measurement and length of sides. It reviews isosceles, scalene, obtuse, right, and acute classifications and includes questions for students to classify some of the...
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Toe to Toe Geo
Students study triangles. For this triangle lesson plan, students compare and classify triangles while milling to music. Students will also trade triangles so they can match up with other similar triangles. Triangles are provided.
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Number & Operations
In this number and operations worksheet, students solve and complete 3 different sections of one problem that uses the Pythagorean theorem to solve. They use the model illustrated to determine the meaning of the Pythagorean theorem....
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Classifying Triangles Based On Properties of Angles
The interactive lesson plan featured here calls for the use of a Smartboard for sorting and classifying shapes. Then, pupils discuss the rules they followed for sorting their shapes, particularly focusing on the properties of angles....
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Sum of Angles on a Triangle
Use this lesson for a basic review of angles. While the activities discussed are outlined, there are no materials provided to make implementation possible. When using this resource, it is necessary to create worksheets and other...
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Angles in a Triangle
In this online math worksheet, students calculate the angles in a triangle given their measurements. This excellent resource allows the students to check their answers, and to get "hints" should they run into difficulties. A terrific...
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Pythagorean Theorem Worksheet
In this online math instructional activity, students use the Pythagorean Theorem to determine if given triangles are "right" triangles. This excellent resource allows the students to check their answers, and to get "hints" should they...
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Cosines
In this online math worksheet, learners practice finding the cosines given 10 different sets of data. When complete, students submit their answers and get instant feedback regarding their accuracy.
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Law of Sines or Sine Rule
In this online math worksheet, high schoolers construct triangles and squares by utilizing the sine rule. This excellent resource allows the students to check their answers, and to get "hints" should they run into difficulties. A...
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Triangle Problems - Find the Height given the Area
In this online math worksheet, learners find the height of 5 triangles given their area. This excellent resource allows the students to check their answers, and to get "hints" should they run into difficulties. A terrific teaching tool!
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Similar Polygons and Triangles Review
In this similar polygons and triangles review activity, students solve 33 short answer problems. Students determine if two given polygons are similar. Students explain the type of similarity if they find two polygons to be similar.
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Easy Worksheet: Types of Triangles
In this types of triangles worksheet, students solve 6 short answer problems. Students identify the type of triangle being described according to side length or angle measure.
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Family Activity: Triangles and Quadrilaterals
In this triangles and quadrilaterals worksheet, students solve 7 short answer problems. Students find objects around the house that are constructed from triangles, parallelograms, trapezoids, squares, rectangles. Students sketch the...
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Perimeter of Triangles and Rectangles
Fifth graders study perimeter. In this math lesson, 5th graders use Cheerios to find the perimeter of various polygons. Students discuss how to figure the perimeter of triangles, squares and rectangles.
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Area-Time to Get in Shape
Students investigate the properties of triangles and parallelograms. In this geometry activity, students calculate the formula used to find the are of a triangle and other polygons. They create a visual model to represent their findings.
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Congruence in Triangles
For this geometry worksheet, students identify and label triangles as being congruent or not. They use the SSS, ASA or SAS as their description. There are 18 questions with an answer key.
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Delta, Delta, Delta
Learners construct equilateral triangles and a 'laser' triangle. In this reflection lesson students build a retro-reflector using mirrors.
Pennsylvania Department of Education
Kites: On the Right Track
Students use the Pythagorean theorem to discover the relationships between the lengths of sides of a right triangle. In this right triangles lesson plan, students use their reasoning and mathematical skills.
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Classifying Polygons
Students study polygons. In this math lesson, students play a game in which they learn the classification system for polygons. Students identify the properties of quadrilaterals.
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Shapes...the Beginning of Geometry
Students identify and name basic shapes and points. In this elementary geometry lesson, students use printable cut outs to name circles, triangles, and squares before playing a game with them. They play a game of "Pin the Tail on the...