Illustrative Mathematics
Lines of Symmetry for Triangles
What can symmetry tell us about triangles? After looking at four examples, learners will come to realize that lines of symmetry are different for equilateral, isosceles, and scalene triangles. Use this guided practice activity as an...
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The Pythagorean Theorem and Classifying Triangles
Through the examination of the relationship between the lengths of the sides of a triangles students will learn the classification of triangles (acute, right, or obtuse).
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Toothpick Triangles
Learners draw a chart (included in the lesson) to use with their investigation. They review terminology of triangles and receive toothpicks to use in the lesson. Beginning with three toothpicks, students form a triangle. They complete...
Illustrative Mathematics
Are These Right?
Is that a right triangle or a wrong triangle? Young mathematicians look at eleven different shapes and use a measuring tool of their choice to determine which triangles have right angles. Consider cutting out sets of the shapes to...
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Exploring Polygons and The Greedy Triangle
Excellent lesson plan! Anne Linehane's geometry story, The Greedy Triangle, offers an opportunity to practice forming various types of polygons with your learners. Using elastic bands (or Chinese jump ropes),...
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Exploring Geometric Figures
Tenth graders explore mathematics by participating in hands-on daily activities. Learners identify a list of different shapes and classify them by shape, size, sides and vertices. They utilize tangrams and geometric pieces to gain...
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Triangle Inequality Theorem
Learners use the inequality theorem to solve triangles and their properties. In this geometry lesson, students are given spaghetti of different lengths and asked to create triangles. They conclude the necessary length needed to make a...
Illustrative Mathematics
All vs. Only Some
All shapes have certain defining attributes that set them apart from others. In order to understand this, young mathematicians look at examples and non-examples of triangles, rectangles, and squares, working as a whole class to create...
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Obtuse Triangles
Fourth graders explore obtuse triangles. In this geometry activity, 4th graders make obtuse triangles with paper and scissors. They determine how to find the center of their triangle.
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Similar and Congruent Triangles
Students create and classify different types of triangles using an online geo-board. They explore the concepts of similar and congruent as they discover how to draw similar and congruent triangles.
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Review of Triangles
Students investigate the Pythagorean Theorem. In this geometry instructional activity, students define angles and sides of right triangles. They calculate the area and surface area using formulas derived by the Pythagorean Theorem.
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Triangles Introduction
Students explore geometry by drawing various shapes in class. In this triangle characteristics lesson, students identify the attributes that classify a shape as a triangle and practice using their bodies to create triangles in class....
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Pythagorean Theorem by Graphic Manipulation
There are many different ways to show a proof of the Pythagorean Theorem. Here is a nice hands-on paper cutting activity that shows a graphic representation. You can even challenge your young Pythagoreans to come up with their own...
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Pythagorean Relationships
Oh that Pythagorean Theorem is so useful. Learners engage in a 45 minute learning activity that requires them to solve for missing angles and sides of a right triangle. They'll use the Pythagorean Theorem to find the rations of sides and...
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CSI Investigation of Congruence and Similarity
Students differentiate between similarity and congruence using polygons. In this geometry lesson, students label triangles based on their properties. They find missing sides and angles using the interior sum theorem.
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Geometry and Measurement
Young scholars view a right triangle displayed by the teacher. Students measure legs and the interior angles of the triangle. They look for a pattern or relationship between the legs and angles. Young scholars use pegboards and string to...
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Compare 2-D Shapes
Second graders explore and analyze plane shapes. In this plane shapes lesson, 2nd graders evaluate shape attributes to classify shapes correctly. Students work in groups to create different shapes.
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Surface Area with Polydrons
Students explore measurements by analyzing geometric shapes. In this surface area lesson, students identify the terms volume, weight, perimeter and area in order to find the requested measurements of specific polygons. Students utilize...
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Properties of Parallelograms
Students identify different properties of parallelograms. In this geometry lesson, students complete problems that proves the theorems and properties of parallelograms. They graph the different shapes on paper.
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Interior and Exterior Angles of Polygons
Students identify interior and exterior angles of polygons. In this geometry lesson, students add interior and exterior angles of polygons. They use angle theorems to solve the problems.
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Powerful Polygons
Students scan the classroom to find different common shapes. They listen as the teacher defines polygon and regular polygon. The teacher demonstrates regular polygons via the Internet and the "Math is Fun" web site. Students go outside...
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Rhombi
Pupils examine the rhombi or diamond shape and compare it to the square. Students are challenged to create as many flat rhombus shapes as possible and develop a definition for the rhombus shape in 20 minutes while working in teams of four.
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Meet the Polygon Family
Fourth graders investigate regular polygons. In this regular polygon lesson, 4th graders explore the attributes of different polygons. Students work in groups to complete a KWL chart regarding polygons.