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
Scale Factors
Is it bigger, or is it smaller—or maybe it's the same size? Individuals learn to describe enlargements and reductions and quantify the result. Lesson five in the series connects the creation of a dilated image to the result. Pupils...
EngageNY
Scale Drawings
Are you searching for a purpose for geometric constructions? Use an engaging approach to explore dilations. Scholars create dilations using a construction method of their choice. As they build their constructed dilation, they strengthen...
Curated OER
Scale factors: Ratios and Proportions
Learners create building and models using scale factors. In this geometry lesson, students apply the properties of ratio and proportion to solve problems. They identify the means and extremes property of cross multiplication.
Illustrative Mathematics
How Many Leaves on a Tree?
This is great go-to activity for those spring or fall days when the weather beckons your geometry class outside. Learners start with a small tree, devising strategies to accurately estimate the leaf count. They must then tackle the...
Mathed Up!
Similar Shapes
Similar shapes are all about the scale. Given seven problems, pupils use scale factors to determine measurements within similar shapes. While solving the problem, scholars also determine whether two figures are similar and use area and...
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.
EngageNY
Scaling Principle for Volumes
Review the principles of scaling areas and draws a comparison to scaling volumes with a third dimensional measurement. The exercises continue with what happens to the volume if the dimensions are not multiplied by the same constant.
Flipped Math
Similar Figures
Use some similar problems to find side lengths. Pupils learn the definition of similar figures and how it relates to corresponding angles and sides. Using the definition, individuals calculate the lengths of missing sides and practice...
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...
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...
Curated OER
Investigating Scale Factors with the Geometer's Sketchpad
Young scholars use Geometer's Sketchpad to examine the scale factor when in is applied to the length of a figure's sides. They look at how the scale factor affects the side lengths, perimeter, and area of the figure that result. They...
Curated OER
Super Size It, Please!
Pupils take photos from a given distance and determine the height of the person using a scale factor. Pupils calculate the ratio of student actual height to student photo height. They take pictures from 3 different distances to see if...
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...
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.
Balanced Assessment
Ostrich and Seahorse
Examine the relationship between ratios and scale. Young math scholars compare ratios of two models. They use the ratios to make a comparison between the two models. Each image uses a different scale, which requires learners to think...
Bowland
In or Out? ... What's Your Decision?
Young mathematicians use photos and video clips to determine if a cricket player is "in" or "out." This analysis occurs using scale factors, distance-rate-time formula, and consideration of precision and accuracy.
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...
Illustrative Mathematics
Floor Plan
A multi-step problem has learners finding the actual area based on a scale drawing and then converting units at the end. Two different solution choices are listed depending on the preference on which step to start first. Both methods can...
EngageNY
How Do Dilations Map Lines, Rays, and Circles?
Applying a learned technique to a new type of problem is an important skill in mathematics. The lesson asks scholars to apply their understanding to analyze dilations of different figures. They make conjectures and conclusions to...
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...
CK-12 Foundation
Area and Volume of Similar Solids: Similar Solids
Five questions make up an interactive designed to boosts knowledge of area and volume of solid figures. Question types include multiple-choice, true or false, and fill-in-the-blank. A scale model changes measurement to provide a visual...
Flipped Math
Unit 6 Review: Similar Figures
After a short review of the material from the Similar Figures Unit, pupils work through 18 problems to further practice the skills from the unit. Scholars apply those skills in the application problems at the end of the review.
EngageNY
How Do Dilations Map Angles?
The key to understanding is making connections. Scholars explore angle dilations using properties of parallel lines. At completion, pupils prove that angles of a dilation preserve their original measure.