Willow Tree
Common Geometric Figures
Geometry could be called the study of figures. An overview of the figures found in a typical geometry course contains a study of different triangles, quadrilaterals, and regular polygons.
Curated OER
Application of Delta-Epsilon Definition of the Limit
Students create a Hexaflexagon using a formula. In this calculus lesson, students apply the definition of delta epsilon as it relates to limit to create a shape using creases. They relate the same rule to triangles and investigate angles.
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Triangle Conjectures
Tenth graders investigate the theorems of ASA, AAS, AAA and ASA. In this geometry lesson, 10th graders discuss the theorems of triangles and how it is used to solve for missing sides or angles. They review how two angles are formed by...
Curated OER
Space Tiling with Captain Planet
Fifth graders Apply the symmetry and angle properties of polygons, using symmetry and angle properties of polygons to solve practical problems. They study tessellates and explain why a shape tessellates.
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More on Tessellations
In this tessellations activity, 10th graders solve 3 different word problems that include creating various tessellations. First, they group pentagons around a vertex so the angles add up to 360 and determine whether the pentagons can...
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Strongest Polygon
Students define and identify shapes by name. In this geometry lesson plan, students construct, identify and compare polygons based on the number of sides. They classify each shape based on their angle sum theorem.
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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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Application of Delta-Epsilon Definition of the Limit
Students investigate the concept of a Limit and how it is used in a variety of problematic situations. They fold paper to help illustrate how to form equilateral triangles and explain how all the angles are the same. The lesson includes...
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Solidly Platonic
When they do, they learn. Using this resource, young mathematicians learn about platonic solids by actually building, touching, and examining the shapes. They connect their observations about the shapes to Euler's formula.
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What Is Hyperbolic Geometry?
Ninth graders discuss the concept of hyperbolic geometry. They complete Internet geometry activities and write essays comparing and contrasting hyperbolic geometry to Euclidean geometry.
Virginia Department of Education
High School Mathematics Geometry Vocabulary Word Wall Cards
Having a good working knowledge of math vocabulary is especially important for geometry learners. Here are 119 pages worth of wonderfully constructed definitions, constructions, formulas, properties, theorems, and postulates. This is a...
Inside Mathematics
Circles in Triangles
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...
EngageNY
Secant Lines; Secant Lines That Meet Inside a Circle
Young mathematicians identify different cases of intersecting secant lines. They then investigate the case where secant lines meet inside a circle.
Willow Tree
The Pythagorean Theorem
There isn't a more popular geometry formula than the Pythagorean Theorem! Learners understand the special side relationships in a right triangle. They use the Pythagorean Theorem to find missing sides and to solve problems. They begin...
Curated OER
Properties of the Centers of a Triangle
High schoolers investigate properties of the four centers of a triangle and explore a special property of the circumcenter and orthocenter of a triangle. This lesson requires the use of Cabri, Jr.
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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...
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Perimeter
In this perimeter activity, 10th graders solve and complete nineteen various geometry problems. First, they find the length of given segments in addition to the perimeter of a kite. Then, students find the value of a variable so that the...
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Algebra/Geometry Institute: Area of Polygons
Students find the area of polygons. For this area of polygons lesson, students find the area of parallelograms, rectangles, squares, and other polygons. They identify each given figure and determine the appropriate formula needed to...
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Pattern Block Polygons
Sixth graders create polygons. In this shapes instructional activity, 6th graders explore prefixes such as oct, tri, quad, pent, etc. and share their findings. Students use pattern blocks to create two different polygons and label them.
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Pythagorean Theorem
Students investigate the concept of the Pythagorean Theorem. After conducting independent practice to find the hypotenuse of a triangle, they work with the teacher using examples in the lesson plan. The direct instruction is delivered...
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Designing a Quilt Pattern
Students create and color a one-patch quilt design based upon a regular hexagon. They examine quilts and photos of quilt designs, read a handout, and complete their quilt design on a worksheet.
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Structures and Shapes
Students make jewelry using different shapes from magazines, tissue paper, cardboard, and other materials. In this making jewelry lesson plan, students complete this hands on activity to discuss how shapes are used.
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Polygons All Around Us!
Students explore the concept of polygon properties. In this polygon properties lesson, students draw polygons with different numbers of sides such as pentagons, octagons, hexagons, etc. Students identify different geometric shapes in the...
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Hidden Jewels of Geometry
Students identify different geometric shapes, and arrange them artistically in original jewelry designs.