Communication is the key. A dozen sample items require scholars to communicate their reasoning involved in arriving at a solution. The PowerPoint from the Gr. 8 Claim 2 - 4 Item Slide Shows series uses a variety of content to illicit...

Transform 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...

Look 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...

Create a personal tree. By visiting an exhibit at the National Museum of Mathematics, the resource introduces the idea of fractals. The exhibit takes an image of the person and creates a tree by repeating scaled images on the shoulders...

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...

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...

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...

Where did the transformation begin? Using a ruler, the narrator of a short presentation shows how to find the center of enlargement for transformed figures. Worksheets provide the class members an opportunity to practice the newly...

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.

Count on the scale to enlarge a figure. The video shows how to create an enlargement given a scale factor and a center of enlargement. The presenter multiplies the vertical and horizontal distance by the scale factor to find the new...

Moving a house is hard work. Given a diagram of a row of houses, scholars determine a set of transformations that would map one house to the next. A second diagram with a coordinate plane helps with the task.

Dive into an activity that may cause a little reflection! Building from the first lesson in the series of two, learners explore transformation using unfamiliar functions. The key takeaway is that applying transformations to any function...

Dilation—more than just an eye opener! A short video introduces the concept of dilating a figure given a center and a scale factor. Using prime notation, the installment of a larger geometry playlist shows how to label dilated images.

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...

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...

Why did it not copy correctly? Using the tools in GeoGebra, pupils explore an image and its preimage. The learners determine what happened with the copying process and determine where they should position the preimage to obtain a...

Stretch the class' knowledge of dilations. With the aid of the rubber band stretcher tool, learners perform dilations. They dilate the triangle by a whole number scale and a fractional scale from two centers of dilation.

Congruence, similarity, and alikeness are ways to describe relationships between figures. While congruence and similarity are common geometric terms, the writer coins the term alikeness to include one-dimensional stretch transformations....

Dilated pupils, the way to prove circles are similar. Using the knowledge of dilations of polygons, class members learn how to dilate a circle to show that it is similar to any other circle. The teacher guides the class through a proof...

Show similarity with a similar approach to congruence. The assessment provides learners with two figures on a coordinate plane. Pupils use the coordinates of the figures and similarity transformations to describe how to show the two...

How can you better explain the standards? A collection of resources gives teachers the resources needed to teach topics within the eighth grade curriculum. Lessons provide engaging activities to use within the classroom. 

Develop a proof of the general case. Pupils develop a proof using transformations to prove the general case that any two circles are similar. The assessment provides minimum information about the two circles.