New ReviewTransform 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...

New ReviewLook at dilations exponentially. Using a fractal from a museum exhibit, the installment from the Math at the Core: Ratios series introduces the term dilation. The presenter points out that dilations can make images either smaller or...

New ReviewMore power to you if you can calculate volumes. Viewers of an informative YouTube video learn about the volumes of similar three-dimensional figures. They see how figures with sides that have a scale factor of n have volumes with a scale...

New ReviewJust how similar are the areas of similar figures? An educational YouTube video describes how to determine the areas of similar figures. Given the area of one figure and the measurements of corresponding sides of each figure, viewers see...

New ReviewScale up a lesson on similarity. Young mathematicians watch a video that investigates the sides of similar figures. They see how to calculate missing sides from the given measures using scale factors.

By definition, a congruent shape remains similar, but similar shapes may or may not be congruent. Scholars watch a video explaining the sometimes-confusing concept. Practice problems ensure pupils demonstrate their understanding to...

Blow up a solid by a scale factor. A section of a larger playlist on basic geometry introduces the ratios of the surface areas and volumes of similar solids. Using the ratios, the video works several examples involving similar figures.

Find the square of the scale factor. A component of a large playlist on geometry discusses the ratios of the perimeters and areas of two similar polygons. The resource shows examples in finding the ratios that lead to a pattern.

Develop an understanding of the scale of similarity. Starting with the concept of congruency, the resource introduces the idea of similarity between two figures. As part of a larger playlist on geometry, it defines similarity and uses...

Investigate and compare scale factors of perimeter and area. Young scholars use an applet to manipulate the sides of similar rectangles. They then make perimeter and area calculations and compare the ratios to finish the second in a...

The definition of similar to a mathematician is a little different than the average person. The first in a sequence of four lessons asks learners to investigates the criteria for similar figures. They compare side lengths between similar...

Let your scholars foreshadow unknown heights. The class uses proportions to solve height problems. Using the ratio of their shadows to their heights, pupils calculate the heights of objects by measuring the shadows. The lesson is the...

Build similar figures from congruent ones. The lesson introduces the concept of rep-tiles. Pupils show that given figures are rep-tiles and discuss the difference between composing and decomposing the tiling patterns.

Zoom in to reveal more of the same. The resource introduces the concept of self similarity. Using a simple example, the video—part of a larger playlist covering geometry concepts—illustrates the meaning of a self similarity figure.

Multiply coordinates to either shrink or enlarge a figure. An informative segment of a geometry playlist introduces dilation on the coordinate plane. The dilations in the resource use the origin as the center of dilation, which makes...

Forget flying, let's go build a kite! Groups build a paper tetrahedron from two 3-D folded figures. They then combine multiple tetrahedrons teams to make a larger tetrahedral kite and compare the surface areas and volumes.

Just a sip will make things smaller. Using Alice’s Adventures in Wonderland as a hook, the lesson introduces the idea of similarity. Pupils use it to find the distances on a map by applying the scale factor and creating similar triangles.

How high and how far does it go? Young scholars learn to count slope by drawing congruent triangles. The activity highlights the difference between positive and negative slope.

Are two angles enough? Given two triangles, the class determines through the definition of similarity and transformations whether the two triangles are similar. Provided with pairs of triangles and measurements, small groups find out...

Are all the measurements scalable? Pupils work in groups or alone to determine whether figures are similar and find any missing side lengths. Then, they calculate the perimeters and areas of the figures. Finally, using the measurements,...

How do you measure a distance where the measurement tool will not reach? Pupils use the concept of similar triangles to perform indirect measurements. The lesson asks teachers to demonstrate the method and lead the class through a set of...

Scale up the dilation factor. Using a dynamic geometry software program, classmates discover the relationship between a pre-image and its image after performing a dilation. Individuals create their own dilations and fellow class members...

Just how similar are dilations to isometries? The lesson builds upon pupils' knowledge of transformations and introduces the concept of dilations to obtain similar figures. Learners find out how to dilate a figure without the coordinate...

What does every circle have in common? Learners explore this question as they prove all circles are similar. A series of activities leads them to this conclusion by identifying transformations.