EngageNY
Congruence, Proof, and Constructions
This amazingly extensive unit covers a wealth of geometric ground, ranging from constructions to angle properties, triangle theorems, rigid transformations, and fundamentals of formal proofs. Each of the almost-forty lessons is broken...
National Council of Teachers of Mathematics
Taking a Spin
It does not divide into 360 evenly, so it cannot work. The resource extends pupils' thinking about rotational symmetry. By asking for a figure with a rotational symmetry of a seemingly impossible angle, the activity requires learners to...
Shodor Education Foundation
Transmographer
Introducing ... the Transmographer. Young mathematicians investigate translations, reflections, and rotations. The applet lets users perform transformations on triangles, squares, and parallelograms.
GeoGebra
Leaping Lizards
Transform lizards onto different locations. The interactive provides a diagram of a lizard and several locations. Pupils use their knowledge of transformations to move the lizard to the different locations and use the tools of GeoGebra...
Mathematics Vision Project
Transformations and Symmetry
Flip, turn, and slide about the coordinate plane. Pupils define the rigid motions and experiment with them before determining the relationships of the slopes of parallel and perpendicular lines. The sixth unit in a nine-part series...
Noyce Foundation
Between the Lines
Explore linear and square dimensions by comparing areas of similar figures. A creative set of five activities designed for elementary through high school classes asks young scholars to compare areas of specific polygons. The first two...
Noyce Foundation
Once Upon a Time
Examine the relationship between time and geometry. A series of five lessons provides a grade-appropriate problem from elementary through high school. Each problem asks learners to compare the movement of the hands on a clock to an angle...
Noyce Foundation
The Shape of Things
Investigate the attributes of polygons. A thorough set of lessons presents problem scenarios for elementary through high school classes. The first lessons focus on basic characteristics of polygons, including the line of symmetry. As the...
Mathed Up!
Translations
Introduce translations as transformations that move figures in horizontal and vertical distances with a video that shows how to translate the figures. A second video covers how to determine the translation that has occurred. Pupils work...
Mathed Up!
Enlargements
Make enlargements with and without centers. Pupils work through seven problems dealing with dilations or enlargements. The first couple items are strict enlargements without centers, while the others have centers. Class members also...
California Mathematics Project
Reflections
Reflections are the geometric mirror. Pupils explore this concept as they discover the properties of reflections. They focus on the coordinates of the reflections and look for patterns. This is the third lesson plan in a seven-part series.
EngageNY
End-of-Module Assessment Task - Geometry (module 1)
Have you hit a wall when trying to create performance task questions? Several open-ended response questions require a deep level of thinking. Topics include triangle congruence, quadrilaterals, special segments, constructions, and...
EngageNY
Review of the Assumptions (part 2)
Is the amount of information getting overwhelming for your geometry classes? Use this strategy as a way to organize information. The resource provides a handout of information studied in relation to triangle congruence. It includes a...
EngageNY
Translations
Learn through constructions! Learners examine a translation using constructions and define the translation using a vector. Pupils then construct parallel lines to determine the location of a translated image and use the vector as a guide.
EngageNY
Review of the Assumptions (part 1)
What was the property again? Tired of hearing this from your pupils? Use this table to organize properties studied and as a reference tool for individuals. Learners apply each property in the third column of the table to ensure their...
EngageNY
Mid-Module Assessment Task - Geometry (Module 1)
How do you prepare class members for the analytical thinking they will need in the real world? An assessment requires the higher order thinking they need to be successful. The module focuses on the concept of rigid transformations...
EngageNY
Correspondence and Transformations
Looking for a strategy to organize the information related to transformations? The materials ask pupils to identify a sequence of rigid transformations, identify corresponding angles and sides, and write a congruence statement. They...
EngageNY
Applications of Congruence in Terms of Rigid Motions
Corresponding parts, congruent parts, congruent corresponding parts—what does it all mean? The resource challenges pupils to identify corresponding parts for pairs of figures. It uses examples of figures that undergo rigid...
EngageNY
Construct and Apply a Sequence of Rigid Motions
Breaking the rules is one thing, proving it is another! Learners expand on their previous understanding of congruence and apply a mathematical definition to transformations. They perform and identify a sequence of transformations and use...
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
Characterize Points on a Perpendicular Bisector
Learn transformations through constructions! Pupils use perpendicular bisectors to understand the movement of a reflection and rotation. They discover that the perpendicular bisector(s) determine the line of reflection and the center of...
EngageNY
Rotations, Reflections, and Symmetry
Lead your high school class on a journey through the world of symmetry and reflections as you discuss geometric principles. Pupils differentiate between reflections and rotations, explore rotational symmetry, and investigate how to...
EngageNY
Reflections
Facilitate creativity in your math class as individuals learn the definition of a geometric reflection and correctly construct a model, as well as its reflected image. They use a perpendicular bisector and circles to elaborate on...
EngageNY
Rotations
Searching for a detailed instructional activity to assist in describing rotations while keeping the class attentive? Individuals manipulate rotations in this application-based instructional activity depending on each parameter. They...