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Grade 8 Mathematics Module 3, Topic A: Dilation

Classroom Resource Information

Title:

Grade 8 Mathematics Module 3, Topic A: Dilation

URL:

https://www.engageny.org/resource/grade-8-mathematics-module-3-topic-overview

Content Source:

EngageNY

Type:

Lesson/Unit Plan

Overview:

Module 3, Topic A begins by demonstrating the need for a precise definition of dilation instead of “same shape, different size” because dilation will be applied to geometric shapes that are not polygons. Students begin their work with dilations off the coordinate plane by experimenting with dilations using a compass and straightedge in order to develop conceptual understanding. It is vital that students have access to these tools in order to develop an intuitive sense of dilation and to prepare for further work in Geometry.

Content Standard(s):

Mathematics
MA2019 (2019)
Grade: 8

23. Use coordinates to describe the effect of transformations (dilations, translations, rotations, and reflections) on two-dimensional figures.

Unpacked Content

Evidence Of Student Attainment:

Students:

Describe the changes occurring to the x-and y-coordinates of a figure after a transformation.

Teacher Vocabulary:

Coordinates
Congruent
Rotation
Reflection
Translation
Dilation
Scale factor

Knowledge:

Students know:

What it means to translate, reflect, rotate, and dilate a figure.
How to perform a translation, reflection, rotation, and dilation of a figure.
How to apply (x, y) notation to describe the effects of a transformation.

Skills:

Students are able to:

Select and apply the proper coordinate notation/rule when given a specific transformation for a figure.
Graph a pre-image/image for a figure on a coordinate plane when given a specific transformation or sequence of transformations.

Understanding:

Students understand that:

the use of coordinates is also helpful in proving the congruence/proportionality between figures.
The relationships between coordinates of a preimage and its image for dilations represent scale factors learned in previous grade levels.

Diverse Learning Needs:

Essential Skills:

Learning Objectives:
M.8.23.1: Define dilation.
M.8.23.2: Recall how to find scale factor.
M.8.23.3: Give examples of scale drawings.
M.8.23.4: Recognize translations.
M.8.23.5: Recognize reflections.
M.8.23.6: Recognize rotations.

Prior Knowledge Skills:

Define scale, scale drawings, length, area, and geometric figures.
Locate/use scale on a map.
Identify proportional relationships.

Alabama Alternate Achievement Standards

AAS Standard:
M.AAS.8.23 Recognize the reflection (across the x or y axis) and translation (across quadrants) of a two dimensional figure on a coordinate plane (limited to non-equilateral rectangles and triangles).

Tags:

compass, coordinates, dilations, geometry, straightedge, twodimensional

License Type:

Custom Permission Type
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Accessibility

Text Resources: Content is organized under headings and subheadings

Comments

There are seven lessons in this topic.

This resource is free for teachers to access and use. All resources required for the lessons are available to print from the site.

This resource provided by:

Author:

Hannah Bradley

ALEX Classroom Resource

Grade 8 Mathematics Module 3, Topic A: Dilation