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I am trying to determine how in-depth to go on this standard, mainly because of all the example problems out there that seem to be going way beyond the language of the standard.
Also, should students be learning just “scale factor” or ratios as in scale of 1:8. What about percent increase or decrease?
Should conversations with students include terminology such as congruent and similar with a congruent figure having a scale of 1 and similar figures having scales making the figure larger or smaller?
Finally, the standard states “geometric figures.” How far should this extend beyond rectangles and triangles?
I can imagine what excesses people might be going to with this standard. The intent of the standard is to prepare for the discussion of similarity and congruence in Grade 8, with some hands on problems that give students a concrete feel for similarity. All of the things you mention in your second paragraph are possibilities, but some judgments have to be made about how much time this takes up in the curriculum and how it supports other more central topics, such as ratios, proportional relationships, and work with rational numbers and their representation as decimals and percents.
I do not think it is necessary to introduce congruence and similarity as formal concepts here; as I said, the point is to prepare for those concepts, not try to do everything at once.
And, any geometric figures that kids have seen are fair game, but you could go a long way with figures made up out of triangles and rectangles.
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