Corbett Maths
Enlargements with Negative Scale Factor
How will a scale factor affect a figure—negatively? Using a grid, the narrator of an engaging video performs a dilation with a negative scale factor. The presenter compares a positive scale factor with a negative scale factor to explain...
Corbett Maths
Enlargements with Fractional Scale Factors
Enlargements make it bigger, right? A video shows viewers how to perform a basic dilation with a fractional scale factor. They learn how to use the scale factor to find the location of the transformed vertex by multiplying the horizontal...
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...
Curated OER
Dilations and Similarity
In this dilations and similarity instructional activity, pupils solve 10 different problems that include various dilations. First, they determine the scale factor of dilations found in the illustrated graphs. Then, everyone determines...
Charleston School District
Constructing Dilations
Pupils multiply the vertical and horizontal distances from the center of dilation by the scale factor. The independent practice prompts the class to analyze the relationship between the image and pre-image. The lesson is part three in a...
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 able...
Corbett Maths
Describing Enlargements
What caused that to happen? Using three aspects, a video demonstrates how to describe an enlargement or dilation. The presenter counts the lengths of the sides to determine the scale factor and a ruler to find the center of dilation.
Curated OER
Geometry Worksheet 9.5: Rotational Symmetry
In this rotational symmetry worksheet, students solve 14 short answer and graphing problems. Students identify the order and magnitude of given figures. Students find the scale factor of a dilation given a graph.
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.
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...
EngageNY
What Lies Behind “Same Shape”?
Develop a more precise definition of similar. The lesson 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 mathematical...
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...
Curated OER
Intuitive Notion of Dilation
In this dilation worksheet, students identify pictures of a dilation. They determine the scale factor and length of missing sides. This one-page worksheet contains ten problems.
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 segments are...
Virginia Department of Education
Dilation
Open up your pupils' eyes and minds on dilations. Scholars perform dilations on a trapezoid on the coordinate plane. They compare the image to the preimage and develop generalizations about dilations.
EngageNY
The Scaling Principle for Area
As they investigate scaling figures and calculate the resulting areas, groups determine the area of similar figures. They continue to investigate the results when the vertical and horizontal scales are not equal.
Corbett Maths
Enlargements Using Ray Method
Figure out what to do when there is no grid to count. Using a ruler and a sharp pencil, the narrator shows how to perform a dilation when the figure is not on a grid. The ray method works by drawing a ray from the center of dilation...
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...
Curated OER
Triangles
In this triangles worksheet, 10th graders solve and graph 8 different problems that include various transformations. First, they write a rule for the composition of a dilation of a scale factor. Then, students determine whether a graphed...
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 find...
Curated OER
A Geometry Worksheet - Similar Triangles
In this similar triangles instructional activity, students find the scale factor of 6 sets of similar triangles. Students find the scale factor of two similar triangles given a sketch with measurements. Students use proportions to find a...
Virginia Department of Education
Transformations
The coordinate plane is a popular place! Identify rotations, reflections, and dilations on the coordinate plane. Pupils work in small groups to match transformations of a figure with the description of the transformation. They perform...
Curated OER
Six Exercise Sets on Transformations
Middle and high schoolers solve fifteen problems from six exercise sets covering transformations, reflections, rotations, and enlargements. The solutions are provided.