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...
K20 LEARN
Quadrilateral Quandary
Classify quadrilaterals quickly. After playing a game to identify quadrilaterals, your young scholars should come away with knowledge of the properties of quadrilaterals. They then apply this knowledge to create a decision tree to ease...
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...
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...
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...
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...
Curated OER
Geometry and Quilting
Students create a quilt square for a class quilt using at least three, two-dimensional geometric figures. They research and write a brief description of at least two different quilt patterns that they find. Pupils discuss that quilts are...
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...