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I see a shift in proportional reasoning in the middle grades away from using a proportion to solve for a missing value. That is all good and I understand that. I am wondering if there is a good place in the common core for items that find the missing side of similar triangles. For example a light pole, shadow item used to determine the height of the light pole. I do not see a natural place for solving this type item in the CCSS. In 8.G it seems the focus is more on understanding similarity than on solving this type of problem. I see this in HS G-CO and SRT as well, emphasis is on proving similarity rather than using similarity to solve for a missing side. Perhaps this is something for which the focus has shifted and solving these types of problems is not an emphasis. Have I answered my own question or am I missing something obvious? Thanks
The Ratios and Proportional Relationships Progression (which can be downloaded here: http://ime.math.arizona.edu/progressions/) discusses problems that include finding unknown side length in the context of 7.G.1 on p. 10 and gives an illustration on p. 11.
7.G.1 is about solving problems involving scale drawings of geometric figures, so it includes similar triangles as a special case.
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