Illustrative Mathematics
Lines of Symmetry for Quadrilaterals
Explore how lines of symmetry help define different categories of quadrilaterals. Looking at a square, rectangle, trapezoid, and parallelogram, young mathematicians discover that each shape has its own, unique symmetry. Encourage your...
Illustrative Mathematics
What is a Trapezoid? (Part 1)
Challenge your class to construct a definition for trapezoids. Looking at four examples and four non-examples, students individually create definitions and use them to classify an unknown shape. Allow for small group and whole-class...
EngageNY
Properties of Parallelograms
Everyone knows that opposite sides of a parallelogram are congruent, but can you prove it? Challenge pupils to use triangle congruence to prove properties of quadrilaterals. Learners complete formal two-column proofs before moving on to...
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...
Mt. San Antonio Collage
Properties of a Parallelogram
More than just a worksheet, the resource provides a thorough guide to navigate through the land of parallelograms. Filled with definitions and theorems, the resource supports learners through problems such as proofs and finding missing...
Illustrative Mathematics
Area of a Trapezoid
Here is a straightforward example of how to apply the Pythagorean Theorem to find an unknown side-length of a trapezoid. Commentary gives additional information on proving that the inside of the trapezoid is a rectangle, but is...
iMagine Machine
The Land of Venn - Geometric Defense
Young mathematicians use their geometry skills to save the Land of Venn in an engaging math game. A fun way to reinforce children's understanding of basic geometric figures and shapes.
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...
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...
Radford University
Quadrilaterals
Connect the quadrilaterals. Working in teams, pupils use a variety of tasks to make connections between special quadrilaterals. With the properties well defined, the groups construct quadrilaterals based on those properties. Learners...
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...
Scholastic
Study Jams! Classify Quadrilaterals
Face the vertex of two-dimensional shapes and discover what each figure requires as part of its classification. With one shape per slide, learners see what makes each shape special and compare it to others with similar qualities.
Curated OER
Application of Properties of Quadrilaterals in the Coordinate Plane
Students apply definitions and theorems to verify special quadrilaterals
using coordinate geometry. They apply the slope formula, the midpoint
formula, and the distance formula to justify that a given quadrilateral is a
parallelogram....
Curated OER
Angle Bisectors and Medians of Quadrilaterals
Young scholars investigate the properties of quadrilaterals formed by angle bisectors of a given quadrilateral and quadrilaterals formed by the medians of quadrilaterals. This Cabri Jr. lesson provides opportunity for conjecture and...
Illustrative Mathematics
Overlapping Rectangle
Challenge young mathematicians' ability to compose and decompose shapes with this fun geometry puzzle. The goal is simple, locate all of the rectangles shown in a picture of three overlapping rectangles. Perform this activity as a whole...
K-5 Math Teaching Resources
2-D Shape Cards
Add some visual support to your elementary geometry lessons with this set of printable shape cards. From triangles and squares to octagons and nanogons, this simple resource can be used in countless ways to develop children's knowledge...
Curated OER
Applications of Properties of Quadrilaterals in the Coordinate Plane
Students explore the concept of quadrilaterals. In this quadrilaterals lesson, students use the slope formula, midpoint formula, and distance formula to justify that a given quadrilateral is a parallelogram.
Curated OER
An Introduction to Quadrilaterals
Students explore the concept of quadrilaterals. In this quadrilateral lesson, students play with a floor tile applet to see that there are many types and characteristics of quadrilaterals including parallelograms, trapezoids, rectangles,...
Shodor Education Foundation
An Introduction To Quadrilaterals
Young geometers investigate and apply properties of quadrilaterals. After a review and discussion of key terms, learners use a computer applet to explore four-sided figures and classify them according to their attributes. The...
Curated OER
Property Lists for Quadrilaterals
Students establish classifications of shapes by various properties (angles, sides, etc.). They introduce the important properties of common shapes. Students develop an awareness of the wide variety of ways the 2-D shapes can be alike.
Illustrative Mathematics
Finding an Unknown Angle
Teach your class how to apply their knowledge of geometry as they explore the unknown. In order to find an unknown angle, students must understand that rectangles have four interior right angles, that right angles have 90 degrees, and...
Curated OER
Measurement: Finding Areas of Rectangles
Gardening geometers construct the formula for the area of a rectangle by viewing a video revolving around two young people, their lawn mowing business, and their need to charge by the square meter. A relevant real-life application lesson!
Curated OER
Constructing Quadrilaterals
High schoolers investigate quadrilateral construction in this geometry lesson. They use Cabri Jr. to construct the different quadrilaterals from the quadrilateral hierarchy given minimal definitions. The lesson reinforces the difference...
Curated OER
Quadrilateral Properties
In this online math worksheet, learners answer "true" or "false" to a variety of statements regarding the properties of quadrilaterals. This excellent resource allows the students to check their answers, and to get "hints" should they...