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Topic: Geometry Question #3
Replies: 39   Last Post: Jun 18, 2009 5:05 PM

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 reuterg@canandaiguaschools.org Posts: 15 Registered: 2/18/05
RE: Geometry Question #3
Posted: Jun 17, 2009 8:12 AM
 att1.html (1.7 K)

Hi all,

I'm just wondering... have we assumed that the rotation was 180 degrees? If the rotation was 181 degrees or 179 degrees, then a dilation of factor -1 is an incorrect choice.

The picture could be interpreted as a dilation, but it must be interpreted as a rotation.

Regards,
George Reuter

Geometry Question #3: We had students identify the transformation as a dilation (of -1). I called the State to see if they would allow credit if a student chose choice #2 dilation. Their response: "No because there are too many assumptions that must be made." And they wanted proof that a rotation of 180 degrees is the same as a dilation of -1. Apparently this is not common knowledge in the math world. Very frustrating.....very frustrating.....

Ed Mertson

Newark Valley High School

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