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...

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. 

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...

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...

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...

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...

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...

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...

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...

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. 

Are congruent shapes compatible? Congruent shapes are identical to one another, and throughout the assessment, young mathematicians identify given shapes as congruent.

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...

To take the longest path, go around—or was that go over? Class members measure scale drawings of a cylindrical vase to find the height and diameter. They calculate the actual height and circumference and determine which is larger.  

How well do your classes understand scale? You'll certainly know after they answer the set of eight questions from an informative and helpful presentation. Questions include items from coordinate geometry, similar triangles, and scale...

Scaling needs to be picture perfect. Pupils use proportional reasoning to find the missing dimension of a photo. Class members determine the sizes of paper needed for two configurations of pictures in the short assessment task.

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...

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.

The Hopewell people of the central Ohio Valley used right triangles in the construction of earthworks. Pupils use the Pythagorean Theorem to determine missing dimensions of right triangles used by the Hopewell people. The assessment task...

Challenge: create an assessment that features higher level thinking from beginning to end. A ready-made test assesses knowledge of dilations using performance tasks. Every question requires a developed written response. 

Picture your pupils using this assessment task. Class members must first determine the measurements of smaller copies of photographs placed next to the original. They then determine the dimensions of the entire sheet of photographs.

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.

Plants never grow at the same rate, and that is the antithesis for this word problem involving multiplication of fractions. On the worksheet, Raul notices that Pablo's seedlings are 1 1/2 times as tall, and Celina's seedlings are 3/4 as...

A pre-test contains questions about transformations that lead to congruent and similar images. It also covers angle relationships associated with triangles and parallel lines intersected by a transversal. 

Build upon the Pythagorean Theorem with the Law of Cosines. The 10th part of a 16-part series introduces the Law of Cosines. Class members use the the geometric representation of the Pythagorean Theorem to develop a proof of the Law of...