West Contra Costa Unified School District
Congruent and Similar Polygons
What's similar about congruent and similar polygons? Young mathematicians first measure the side lengths and angles of given figures. They use these measurements to determine relationships between side lengths and angles of congruent and...
EngageNY
Fundamental Theorem of Similarity (FTS)
How do dilated line segments relate? Lead the class in an activity to determine the relationship between line segments and their dilated images. In the fourth section in a unit of 16, pupils discover the dilated line segments are...
Curated OER
Creating Parallel Lines and Transversals
Have your class create parallel lines. High schoolers will learn how to identify the different angles created by a parallel line cut by a transversal. Then, they identify and name similar and different angles.
Curated OER
Secants, Tangents and Arcs
Students identify chords and angles. For this geometry lesson, students calculate the length of the chords inside and outside of-the circle. They differentiate between tangent and secant lines.
Curated OER
Triangle Congruence
Students use web applet to create congruent triangles. In this geometry lesson, students differentiate between congruent and similar. They create shapes online and drag those shapes around to create visuals of triangles.
Curated OER
Why Doesn't SSA Work?
Students investigate the relationship between angles and their sides. In this geometry lesson, students prove why SSA does not work as a true angle side relationship theorem.
Curated OER
Corresponding Parts of Similar Triangles
Here is a lesson that has learners take a look at corresponding parts of similar triangles, ratios of similarity, reductions and enlargements. They'll manipulate the scale factor (r) to observe the changes in similar triangles and then...
Curated OER
"Sir Cumference and the First Round Table" by Cindy Neuschwander
Students analyze characteristics of various 2 dimensional shapes and explore their properties and use various vocabulary terms to discuss geometric relationships.
Curated OER
Geometry Geopardy
Third graders participate in a game in order to review geometric concepts.
Improving Measurement and Geometry in Elementary Schools
The Sum of the Interior Angles of a Polygon
Junior geometers discover that polygons can be decomposed into triangles and that the number of triangles can be determined by a rule. Note that the Geometer’s Sketchpad® software is required to carry out all components of this...
Curated OER
Geometry Finding Pentominoes
Students explore the characteristics of geometric shapes. In this geometric shapes lesson, students use tiles to draw pentominoes. Students participate in various learning center activities focused on configuring pentominoes.
Curated OER
Pythagorean Theorem: Triangles and Their Sides
Young scholars investigate triangles and their relationship to each other. In this geometry lesson, students solve right triangles using the properties of the Pythagorean Theorem. They differentiate between right, acute, straight and...
Curated OER
Triangle Inequality Theorems Investigation
Students estimate and measure triangles. In this geometry lesson, students identify the relationship between three sides and a triangle. They use the inequality theorem to decide if a triangle will be formed or not.
Curated OER
Exploring Harmonic Conjugates
High schoolers investigate harmonic conjugates using Cabri Software or the Ti Calculator to analyze harmonics. They explore different angles measurements as they move their circles around and solve problems.
EngageNY
Complex Numbers and Transformations
Your learners combine their knowledge of real and imaginary numbers and matrices in an activity containing thirty lessons, two assessments (mid-module and end module), and their corresponding rubrics. Centered on complex numbers and...
Inside Mathematics
Quadrilaterals
What figure is formed by connecting the midpoints of the sides of a quadrilateral? The geometry assessment task has class members work through the process of determining the figure inscribed in a quadrilateral. Pupils use geometric...
Everyday Mathematics
Mathematics Within: Slope and Triangles
Learners discover a method for determining the slope of a line by creating and comparing similar triangles. They fold coordinate grids to make three similar triangles then measure the sides to compare the relationships between the...
Curated OER
Sphere Dressing
Geometric design makes a fashion statement! Challenge learners to design a hat to fit a Styrofoam model. Specifications are clear and pupils use concepts related to three-dimensional objects including volume of irregular shapes and...
Curated OER
Special Right Triangles
Using the Pythagorean Theorem to solve for missing angles, young scholars evaluate right triangles and their properties.
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...
University of Nottingham
Drawing to Scale: A Garden
See how design and geometry go hand in hand. The activity asks learners to use geometry to design a backyard garden given dimensions of each feature. Scholars work with ratios and scale to develop an accurate scale drawing that includes...
Virginia Department of Education
Properties of Quadrilaterals
What type of quadrilateral is that? Discover the difference between the types of quadrilaterals. Small groups investigate types of quadrilaterals using geometry software to find their properties. To keep track of the different...
Curated OER
Making Rectangles
Students study rectangles. In this math activity, students use numbers, measurements and geometry to draw rectangles of varying sizes.
Curated OER
Angle Measurement and the AD-1 Aircraft
Students represent and solve problems using geometric models and apply geometric properties and relationships. They also practice constructing and measuring angles. By constructing, drawing, visualizing, and comparing geometric figures...