Curated OER
Problem Solving Using Power Polygons
Students investigate geometric shapes by creating figures on a plane. In this polygon lesson, students complete a worksheet based on the angles in a power polygon. Students identify the different types of polygons and define their...
Curated OER
Perimeters, Patterns, and Conjectures
Students discover patterns and write conjectures relating to perimeters and polygons. Working in cooperative learning groups, they use manipulatives and graphic organizers to solve problems then answer a series of questions in which they...
Curated OER
Exploring Geometric Constructions of Parabolas
Pupils are introduced to the construction geometrically of parabolas. Using a software program, they identify lines, segments and midpoints. They label the parabolas properties and characteristics and use a formula to determine the...
Curated OER
Math: A Geometric Neighborhood
Pupils, as a final project, draw a picture of their ideal neighborhood on a sunny day. In addition to the sun, their drawings include homes, trees, streets, and selected objects. Each object in their drawing has a written description...
Curated OER
Proofs
In this geometric proof worksheet, students compose 20 triangle congruency proofs. Students will decide if there is enough information in problems 1-6 to prove if any triangles are congruent. In problems 17 to 20, students use given...
Curated OER
Conjectures For Intersecting Circles
Students identify properties of circles. In this geometry lesson, students identify the center of two intersecting circles.They use Cabri software to create circles and move it around to make observation.
Inside Mathematics
Rhombuses
Just what does it take to show two rhombuses are similar? The assessment task asks pupils to develop an argument to show that given quadrilaterals are rhombuses. Class members also use their knowledge of similar triangles to show two...
EngageNY
Properties of Dilations
Investigate dilations to learn more about them. The second segment in a series of 16 provides a discussion of properties of dilations by going through examples. The problem set provides opportunities for scholars to construct dilations.
Inside Mathematics
Conference Tables
Pupils analyze a pattern of conference tables to determine the number of tables needed and the number of people that can be seated for a given size. Individuals develop general formulas for the two growing number patterns and use them to...
EngageNY
Unknown Angle Proofs—Proofs with Constructions
Provide your emerging mathematicians with the tools to learn as they incorporate auxiliary lines to solve unknown angle proofs in this continuing segment. They decipher information from a diagram to uncover the missing pieces and...
Curated OER
Exploring Special Segments in Triangles
Young scholars discover that four special segments have a common intersection point. They identify the position of the intersection point in triangles. They produce conjectures about areas of the divided triangles.
Curated OER
Polydron Fun
Young scholars investigate nets as they relate to volume and area. In this geometry lesson, students use nets as a visual to deepen their understanding of surface area and volume of objects. They make conjectures about different objects...
Ohio Department of Education
I Can Name that Angle in One Measure! - Grade Eight
Collaborative groups work with geometry manipulatives to investigate conjectures about angles. They create a graphic organizer to use in summarizing relationships among angles in intersecting, perpendicular and parallel lines cut by a...
Curated OER
Which Quadrilateral Is It?
Young scholars prove conjectures about geometric figures on the plane or in space using coordinate geometry. They develop fluency in operations with real numbers, vectors and matrices using mental computation or paper-and-pencil...
Curated OER
The Pythagorean Theorem
Young scholars create both a visual and formal proof of the Pythagorean theorem, as well as view four additional geometric demonstrations of the theorem. They construct a square and conjecture the following theorem: The sum of the areas...
Curated OER
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...
Curated OER
Investigating the Slopes of Parallel and Perpendicular Lines
High schoolers investigate parallel and perpendicular lines. They use Cabri Jr. to construct and explore the relationships between the slopes of parallel and perpendicular lines. The drawing and measurement tools available with Cabri Jr....
Curated OER
Measuring Angles in a Quadrilateral
High schoolers explore quadrilaterals in this geometry lesson. They will draw a quadrilateral, measure the angles, and find the sum of the measures of the interior angles using Cabri Jr. The interactive capabilities of Cabri Jr. allow...
Curated OER
Exploring the Centroid of a Triangle
Pupils examine the centroid of a triangle as they use Cabri Jr. to construct a triangle and its medians. The dynamic nature of the software allows learners to measure the lengths of the segments in the triangle and conjecture and verify...
Curated OER
Inscribing a Circle in a Triangle
Pupils investigate inscribing a circle in a triangle. They use Cabri Jr. to draw a triangle, locate the incenter, and use the distance from the incenter to a side of the triangle to inscribe a circle. The dynamic nature of the geometry...
Curated OER
Investigating Lengths of Segments in a Triangle
Pupils explore the midsegment of a triangle in the geometry lesson. They draw and measure the segment joining the midpoints of the two sides of a triangle and compare its length to the length of the third side of the triangle. The...
Curated OER
Measuring Angles in a Triangle
High schoolers investigate the sum of the measures of the angles of a triangle. They draw a triangle and measure the interior angles. Using Cabri Jr., learners find the sum of the measures of the interior angles. The lesson provides an...
Curated OER
Spherical Geometry: A Global Perspective
Students investigate spherical geometry using a globe and an apple. In this spherical geometry lesson plan, students translate Euclidean geometry terms to spherical geometry terms using a globe. They answer 3 questions about spherical...
Curated OER
Betweenness and the Sum of Parts
High schoolers differentiate lines and angles using betweenness in this geometry lesson. They differentiate angles and lines using Cabri Jr. and analyze the data and make conjecture.