West Contra Costa Unified School District
Investigating Similar Triangles
Let your use of the resource be in proportion to its usefulness. Pupils investigate similar triangles by measuring side lengths and considering given angle measures. The results of the investigation help develop generalizations about...
Curated OER
Constructing Perpendicular Bisectors
Tenth graders investigate parallel lines and the angles formed when cut by a transversal. In this geometry lesson, 10th graders construct perpendicular lines and discuss midpoint, segments and perpendicular bisectors. They relate...
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Measurement
Fifth graders measure specified distances when given perpendicular lines. For this measurement lesson plan, 5th graders draw the lines themselves.
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Lines and Angles
Students explore Geometry with Twizzlers Candy, pipe cleaners, paper, pencils, and protractors. They manipulate these items to create different angles introduced by the teacher.
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More About Similar Triangles
Determine whether two triangles are similar. The lesson presents opportunities for pupils to find the criterion needed to show that two triangles are similar. Scholars use the definition of similarity to find any missing side...
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Composition of Reflections
Students perform reflections and translations of polygons. In this geometry lesson, students perform reflection in two parallel lines. They use Cabri to observe the transformation and rotations of each shape.
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Measuring the Earth
Students use principles of geometry to measure the circumference of the Earth. In this applied geometry lesson, students use mathematics to determine scientific information. They make measurements, calculate the central angle, and...
Texas Instruments
Investigating Segments in a Quadrilateral
Investigate the properties of the shape formed by connecting the midpoints of adjacent sides of a quadrilateral. In this properties of the shape formed by connecting the midpoints of adjacent sides of a quadrilateral lesson, high...
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Find Someone Who........
Fifth graders identify, describe, and classify lines, line segments, rays, and angles. When given a diagram of a line, they classify the line as perpendicular, parallel, intersecting, vertical, horizontal, and/or diagonal.
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Angling Your Way Through a Picture
Students look at the geometry in an artwork. In this art history/geometry lesson, students research the artist Charles Sheeler and look at his painting Stacks in Celebration. They find the different types of lines, angles, and...
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Our Geometic World
Young scholars walk around the neighborhood and identify various polygons and lines in buildings, nature and other objects. They design a building using various geometric patterns, shapes and lines. Students complete a descriptive...
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Light Bounce
Learners solve problems involving triangles. In this geometry instructional activity, students apply properties of triangles to find the missing angles and sides. They identify angles of parallel lines cut by a transversal.
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Geometry: Lesson 1: Points, Lines, Segments, Angles
Fourth graders examine the concepts of, draw, and label points, lines, segments, and angles, They draw, label, and identify horizontal, vertical, intersecting, parallel, and perpendicular lines. They complete an associated worksheet that...
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Fabulous Fractals
Learners view a video to discover how patterns in nature relate to math. They explore the concept of exponential growth by observing and creating fractals. They solve and design word problems.
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Angles, Parallel Lines, and Polygons
Students examine how to investigate polygons using an instrument of their own construction. They should be able to prove the general formula for the number of degrees in any polygon (including a triangle). Finally they investigate an...
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Folding to Make Shapes
Second graders identify different polygons and their attributes. In this geometry lesson, 2nd graders get to know polygons by studying the vocabulary and finding polygons in their classroom. They create these shapes and then find their...
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Equations of Lines
Young scholars define slope, and practice finding the slope of lines through given points. They determine the angle of inclination. Students find the relationship between the slope and the tangent of the lines. Young scholars determine...
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The Tipping Point
Young scholars rewrite word problems and solve using math. In this word problem lesson, students gather data and observe the data. They relate this process to the scientific method and math. They review their data to be able to answer...
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Properties of Special Quadrilaterals
Teach your mathematicians how to identify the properties of quadrilaterals. In this geometry lesson plan, students solve for missing angles and sides of a special quadrilateral. They use the TI to move the sides around and create...
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Flip's Flag
Fifth graders apply the symmetry and angle properties of polygons and use fractions to express the relationships between the areas of rectangles, squares, and triangles. They analyze various country flags and develop mathematical...
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Midsegments of a Triangle
Students analyze midsegments of triangles in this lesson plan. They use Cabri Jr. software to observe the relationships between interior angles and midsegments of triangles. Specific instructions for creating this lesson plan in Cabri...
Curated OER
Geometric Lines: Parallel / Transversal / Perpendicular
Students in grade 7 and 8 work on outcomes related to spatial sense and geometric concepts, properties, and relationships. The lesson integrates technology and helps students be exposed to multimedia.
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Definition of Rotation and Basic Properties
Examine the process of rotating images to visualize effects of changes to them. The fifth instructional activity of 18 prompts pupils to rotate different images to various degrees of rotation. It pays special attention to rotations in...
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Informal Proof of AA Criterion for Similarity
What does it take to show two triangles are similar? The 11th segment in a series of 16 introduces the AA Criterion for Similarity. A discussion provides an informal proof of the theorem. Exercises and problems require scholars to apply...