I need help finding a way to teach the standard of reproducing a scale drawing at a different scale for my 7th grade math class.
$\begingroup$
$\endgroup$
1
-
$\begingroup$ If this is their first time with scaling, I would start with quad (graph) paper and colored pencils. You could also supplement it with some basic number theory for brighter students. $\endgroup$– dtldarekCommented Apr 8, 2014 at 16:37
Add a comment
|
1 Answer
$\begingroup$
$\endgroup$
An important concept in scaling figures at this level is the connection to proportionality (which is obvious to many advanced math users, but is not obvious to many students and even teachers).
It's unclear what sort of activity you're thinking about. I have produced Geometer's Sketchpad sketches that are used with Sketch Explorer on the iPad, and these sketches were used as dynamic activities in interview items as part of a study of 6th and 7th grade math teachers' knowledge of concepts of proportion, scale, fraction, and ratio. I have found that, while constant of proportionality is obviously an important concept in understanding the relationship between similar but differently-scaled drawings, this is not used as commonly as one would expect.
Therefore, it might be useful to your students to manually construct scaled drawings (construct drawing B from drawing A), determining a constant of proportionality in the relationship between the corresponding linear measures. Even 7th grade students may be surprised that there is a constant relationship in all the corresponding linear measures (including widths, heights, perimeters, circumferences, etc). Once this relationship is discovered / understood, any scaled drawing can be reproduced. Angles need not be measured; any point in the scaled drawing can be located by finding its horizontal and vertical distances from the nearest sides.
Cheers!
