Illustrative Mathematics
Similar Triangles
Proving triangles are similar is often an exercise in applying one of the many theorems young geometers memorize, like the AA similarity criteria. But proving that the criteria themselves are valid from basic principles is a great...
Curated OER
The Gettysburg Address by Abraham Lincoln
"The Gettysburg Address" is the basis of a series of activities that not only model for learners how to conduct a close reading of a text, but also how a close reading can help them comprehend a difficult text. The detailed, step-by-step...
EngageNY
Stretching and Shrinking Graphs of Functions
Why is that graph wider? Pupils learn about stretching and shrinking graphs of square root, absolute value, cubic, and quadratic functions. They study both vertical and horizontal stretches and shrinks in addition to reflections.
Mathematics Assessment Project
Representing Functions of Everyday Situations
Functions help make the world make more sense. Individuals model real-world situations with functions. They match a variety of contexts to different function types to finish a helpful resource.
Mathematics Vision Project
Geometric Figures
Logical thinking is at the forefront of this jam-packed lesson, with young mathematicians not only investigating geometric concepts but also how they "know what they know". Through each activity and worksheet, learners wrestle with...
EngageNY
Looking More Carefully at Parallel Lines
Can you prove it? Making assumptions in geometry is commonplace. This resource requires mathematicians to prove the parallel line postulate through constructions. Learners construct parallel lines with a 180-degree rotation and then...
EngageNY
Definition of Rotation and Basic Properties
Examine the process of rotating images to visualize effects of changes to them. The fifth lesson of 18 prompts pupils to rotate different images to various degrees of rotation. It pays special attention to rotations in multiples of 90...
Virginia Department of Education
Transformation Investigation
Graph it! Investigate transformations with a graphing calculator. Pupils graph sets of linear functions on the same set of axes. They determine how changes in the equation of a linear function result in changes in the graph.