Howard Hughes Medical Institute
What van Leeuwenhoek Saw
When van Leeuwenhoek saw cells and single-celled organisms for the first time, he knew these small things were a big deal! Share his discoveries with young learners through a narrated video, model-building activity, and scale study....
Benjamin Banneker Association
Celebrate Benjamin Banneker
Inventor, astronomer, surveyor, mathematician, clock maker. Learners celebrate the life of Benjamin Banneker by building creative analog clocks, making scale models, and solving problems related to surveying. The activities model the...
National Council of Teachers of Mathematics
Scale Factor
Does doubling mean everything doubles? Learners adjust the scale factor between two rectangles. Using the calculated measurements, pupils investigate the ratios between the lengths, perimeters, and areas of the rectangles.
Virginia Department of Education
Attributes of a Rectangular Prism
A change is coming. Pupils use unit cubes to investigate how changes in the length, width, and/or height affects volume and surface area. They extend the results to write and test predictions on the effect of changing multiple sides on...
EngageNY
Solving Area Problems Using Scale Drawings
Calculate the areas of scale drawings until a more efficient method emerges. Pupils find the relationship between the scale factor of a scale drawing and the scale of the areas. They determine the scale of the areas is the square of the...
EngageNY
Computing Actual Lengths from a Scale Drawing
The original drawing is eight units — how big is the scale drawing? Classmates determine the scale percent between a scale drawing and an object to calculate the length of a portion of the object. They use the percent equation to find...
Teach Engineering
Scale Model Project
Try your hand at scale models. Scholars create a scale model of an object using a scale factor of their choice. As part of the project, they give presentations on their processes and calculations. This is the last installment of the...
Noyce Foundation
Surrounded and Covered
What effect does changing the perimeter have on the area of a figure? The five problems in the resource explore this question at various grade levels. Elementary problems focus on the perimeter of rectangles and irregular figures with...
EngageNY
End-of-Module Assessment Task: Grade 7 Mathematics Module 4
Asses the class to determine their knowledge of proportional relationships involving percents. Class members work through the nine-question assessment with a variety of percent problems. The multi-step problems involve simple interest,...
EngageNY
Changing Scales
Pupils determine scale factors from one figure to another and the scale factor in the reverse direction. Scholars compute the percent changes between three figures.
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...
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
An Exercise in Creating a Scale Drawing
Design your dream classroom. The lesson plan contains an exercise to have teams create a scale drawing of their dream classroom. Pairs take the measurements of their classroom and furniture and create a scale factor for them. To finish...
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...
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 transformations.
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...
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...
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
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.
Balanced Assessment
House Plan
A short assessment has individuals determine the scale of a house plan. They use the scale to calculate the size of a door and window that need to be replaced, and then divide a bedroom in two, calculating the size of rooms created.
Balanced Assessment
Scale Charts
Develop scales using tables. Pupils complete charts to show equivalent scale factors before using the completed tables to determine the sizes of scale drawings. They finish the lesson and demonstrate their understanding by completing a...
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
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...
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...