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EngageNY
Examples of Dilations
Does it matter how many points to dilate? The resource presents problems of dilating curved figures. Class members find out that not only do they need to dilate several points but the points need to be distributed about the entire curve...
EngageNY
Dilations on the Coordinate Plane
Dilations from the origin have a multiplicative effect on the coordinates of a point. Pupils use the method of finding the image of a point on a ray after a dilation to find a short cut. Classmates determine the short cut of being...
EngageNY
Properties of Dilations
Investigate dilations to learn more about them. The second segment in a series of 16 provides a discussion of properties of dilations by going through examples. The problem set provides opportunities for scholars to construct dilations.
EngageNY
Informal Proofs of Properties of Dilations
Challenge the class to prove that the dilation properties always hold. The lesson develops an informal proof of the properties of dilations through a discussion. Two of the proofs are verified with each class member performing the...
EngageNY
What Lies Behind “Same Shape”?
Develop a more precise definition of similar. The lesson plan begins with an informal definition of similar figures and develops the need to be more precise. The class learns about dilations and uses that knowledge to arrive at a...
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...
Illustrative Mathematics
Dilating a Line
High School geometers verify through experimentation certain properties about dilations. This multi-step problem challenges them to construct examples of dilations to verify specific facts, the final step provides an opportunity to more...
EngageNY
The Hunt for Better Notation
The matrix — it's not just a movie. The lesson introduces the concept of 2 x 2 matrix multiplication as a way to represent linear transformations. Class members determine when a linear transformation represented as matrix...
EngageNY
When Can We Reverse a Transformation? 3
When working with matrix multiplication, it all comes back around. The 31st portion of the unit is the third lesson on inverse matrices. The resource reviews the concepts of inverses and how to find them from the previous two lessons....
Bowland
Three of a Kind
One is chance, two is a coincidence, three's a pattern. Scholars must determine similarities and differences of a regular hexagon undergoing dilation. They look at lengths, angles, areas, and symmetry.
Mathed Up!
Mixed Transformations
Viewers learn how to identify and perform a variety of transformations with a video that provides seven items on transformations. Pupils demonstrate their understanding of dilations, reflections, rotations, and translations. The video...
EngageNY
Fundamental Theorem of Similarity (FTS)
How do dilated line segments relate? Lead the class in an activity to determine the relationship between line segments and their dilated images. In the fourth section in a unit of 16, pupils discover the dilated line...
EngageNY
Mid-Module Assessment Task: Grade 8 Module 3
How well does the class understand dilations? The three-part assessment presents problems related to the properties of dilations. Pupils perform dilations and determine whether a dilation is responsible for a specific image.
EngageNY
First Consequences of FTS
Challenge the young mathematicians to find the exact coordinates of a dilated point. The fifth segment in a 16-part series introduces the class to the converse of the Fundamental Theorem of Similarity. Scholars use the theorem to...
EngageNY
Similarity
Use the coordinate plane to show two figures are similar. The lesson incorporates congruence transformations and dilations to move a figure on to another figure. Pupils determine that if a similarity transformation exists...
CCSS Math Activities
Smarter Balanced Sample Items: 8th Grade Math – Target G
Transform the thinking of transformations with six sample items that illustrate the first four standards in the eighth grade geometry domain. Items use the coordinate plane to transform figures and analyze the relationship of the figures...
CCSS Math Activities
Smarter Balanced Sample Items: 8th Grade Math – Claim 3
Communication is the key. A dozen sample items require scholars to communicate their reasoning involved in arriving at a solution. The PowerPoint from the Gr. 8 Claim 2 - 4 Item Slide Shows series uses a variety of content to...
EngageNY
Exploiting the Connection to Cartesian Coordinates
Multiplication in polar form is nice and neat—that is not the case for coordinate representation. Multiplication by a complex number results in a dilation and a rotation in the plane. The formulas to show the dilation and rotation are...
EngageNY
Mid-Module Assessment Task - Geometry (Module 2)
Challenge: create an assessment that features higher level thinking from beginning to end. A ready-made test assesses knowledge of dilations using performance tasks. Every question requires a developed written response.
Illustrative Mathematics
Similar Circles
Young geometers flex their transformation muscles in this brief but powerful exercise using dilations and translations to develop the similarity of circles. The plan provides guidelines to help learners navigate a pair of...
EngageNY
Discovering the Geometric Effect of Complex Multiplication
Does complex number multiplication have the class spinning? Here's a resource that helps pupils explore and discover the geometric effect of multiplying complex numbers. In the 14th installment in the 32-part unit groups look at the unit...
Mathed Up!
Negative Scale Factor
Class members investigate the effect of a negative scale factor dilation on coordinate shapes as they watch a short video that shows an example of a geometric figure undergoing a dilation with a negative scale factor. Learners then try a...
Charleston School District
Review Unit 2: Congruence and Similarity
Review for the test with a comprehensive list of terms and concepts for the unit on congruence and similarity. It divides divides the sections in the order of the lessons presented during the unit.
EngageNY
End-of-Module Assessment Task - Grade 8 Mathematics (Module 3)
Everything the class knows about similarity in one small package. The last portion of a 16-part series is a three-question assessment. In it, pupils demonstrate their application of similar figures and their associated...