Curated OER
Symmetries of a Quadrilateral I
Learners examine the properties of quadrilaterals from the point of view of rigid motion. Different types of quadrilaterals are characterized by their symmetries, so learners explore the symmetries of a described quadrilateral to...
Illustrative Mathematics
A Midpoint Miracle
Young geometers develop one of the fundamental properties of quadrilaterals (connecting side midpoints gives a parallelogram) in this short but thought-provoking exercise. Using a combination of hands-on techniques and abstract algebraic...
Illustrative Mathematics
What Shape Am I?
Sharpen your pencil and grab a ruler, it's time to draw some quadrilaterals! Given the definition of a parallelogram, rectangle, and rhombus, learners draw examples and nonexamples of each figure. The three definitions are...
Illustrative Mathematics
Right Triangles Inscribed in Circles II
So many times the characteristics of triangles are presented as a vocabulary-type of lesson, but in this activity they are key to unraveling a proof. A unique attack on proving that an inscribed angle that subtends a diameter must be a...
Illustrative Mathematics
Alike or Different Game
How are a circle and triangle alike? How are they different? These are the types of questions children will answer while playing this fun geometry game. Including a variety of conventional and unconventional shapes, this activity allows...
Illustrative Mathematics
What is a Trapezoid? (Part 2)
This collaborative activity investigates the meaning of a trapezoid and a parallelogram. It begins by presenting two different definitions of a trapezoid. Learners are to reason abstractly the difference between the two definitions and...
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...
Illustrative Mathematics
Extensions, Bisections and Dissections in a Rectangle
Gaining practice in translating a verbal description into a diagram and then an equation is the real point of this similar triangles exercise. Once the diagram is drawn, multiple methods are provided to reach the conclusion. An effective...
Curated OER
Task: Grain Storage
Farming is full of mathematics, and it provides numerous real-world examples for young mathematicians to study. Here, we look at a cylinder-shaped storage silo that has one flat side. Given certain dimensions, students need to determine...
Education Development Center
Finding Parallelogram Vertices
Four is the perfect number—if you're talking about parallelograms. Scholars determine a possible fourth vertex of a parallelogram in the coordinate plane given the coordinates of three vertices. They read a conversation...
Texas Instruments
Texas Instruments: Exploring Quadrilateral Properties Using Cabri
Students can use Cabri Jr. to learn about the properties of quadrilaterals as well as learn about the relationships between quadrilaterals.
Texas Instruments
Texas Instruments: Properties of Quadrilaterals
This activity focuses on the properties of special quadrilaterals. [Requires Adobe Reader.]
Los Angeles County Office of Education
Los Angeles County Office of Education: Quadrilateral Quest
Use your knowledge of properties of quadrilaterals to correctly match quadrilaterals.
Texas Instruments
Texas Instruments: Investigating Properties of the Diagonals of Quadrilaterals
In this activity, students will explore the properties of the diagonals of various quadrilaterals. They will use a quadrilateral hierarchy chart to examine the relationship between the quadrilaterals.
Texas Instruments
Texas Instruments: Discovering the Quadrilateral Properties
This activity will use Cabri Jr. to allow students' the ability to discover all of the properties of each quadrilateral, rather than simply copying them out of a textbook.
Texas Instruments
Texas Instruments: Special Midpoint Quadrilaterals
Midpoint Quadrilaterals are quadrilaterals that are formed when consecutive midpoints of a quadrilateral are connected. This activity will use Cabri Jr. to investigate what properties an exterior quadrilateral has if its midpoint...
Texas Instruments
Texas Instruments: Cyclic Quadrilaterals
Students construct cyclic quadrilaterals and investigate their properties. They determine which quadrilaterals from the quadrilateral hierarchy are cyclic.
Texas Instruments
Texas Instruments: Investigating Properties of Kites
In this activity, students construct kites and investigate their properties. They also relate the properties to squares and rhombi.
Texas Instruments
Texas Instruments: Investigating Segments in a Quadrilateral
In this activity, students use the tools of Cabri Jr to test their knowledge of geometry. They investigate the properties of the shape formed by connecting the midpoints of adjacent sides of a quadrilateral.
Texas Instruments
Texas Instruments: Properties of Parallelograms
In this activity, students go through the process of proving a quadrilateral to be a parallelogram. They understand the various characteristics of a parallelogram.
Texas Instruments
Texas Instruments: Angle Bisectors and Medians of Quadrilaterals
In this activity, students will construct angle bisectors and medians in quadrilaterals and explore the properties that appear to be true for four-sided figures. They may find it necessary to review the definitions and properties of...
Texas Instruments
Texas Instruments: Discovering Properties of Parallelograms, Kites & Trapazoids
This activity allows the teacher to cover the properties of a parallelogram, rectangle, rhombus, square, kite, and trapezoid in two days (90 min. block scheduling) Using a group setting students discover these properties using the Cabri...
CK-12 Foundation
Ck 12: Inscribed Quadrilaterals in Circles
[Free Registration/Login Required] Students will explore quadrilaterals inscribed in circles with this interactive activity. Click 'Challenge Me' to answer a practice question.
Texas Instruments
Texas Instruments: Investigating Properties of Trapezoids
This activity uses the graphing calculator to investigate trapezoids. Numerous supplementary materials are included. [Requires Adobe Reader.]