Monday, December 17, 2012

An Approach to Construction Example 5 #ccssimath #commoncore

Again, image a few things from the onset... Draw PA and construct parallels to it through both B and C.  Construct the perpendicular to these parallels through A.  The following explains how to finish it off...

another_approach.doc Download this file

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Saturday, December 15, 2012

Geometry and #CommonCore #ccsimath

I enjoy reading this blog

Here's an attempt.  You'll have to imagine a couple of things since I don't have the right equipment on this computer: the parallel lines were "constructed" and the curve shown is a compass mark of length AB with center at A.

Construction Example 1 - Construct the perpendicular bisector of the line connecting the two points on the cressent.

Construction Example 2 - Construct the pendicular to segment OB through O, intersecting arc AB at R. Then bisect angle AOR to locate P on arc AB.

Construction Example 3 - Construct the perpendicular bisector of segment XY, this line will intersect line l in the desired point O.

Construction Example 4 - Construct the perpendicular to segment AB at A, then bisect it.  At point B, construct an equilateral triangle having one side on segment AB.  Extend the lines to locate point C in triangle ABC.

Still thinking about Construction Example 5


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Thursday, December 13, 2012

How Mediocre #Math Programs Gain Market Share in the US [ #edresearch ]

Private Data - The Real Story:
A Huge Problem with
Education Research

R. James Milgram

Professor of Mathematics Emeritus,
Stanford University, 12/7/2012


A very influential paper on improving math outcomes was published in 2008. The authors refused to divulge their data claiming that agreements with the schools and Family Educational Rights and Privacy Act (FERPA) rules prevented it.

  • It turns out that this is not true.
  • The claimed legal foundations do not say what these authors said they do.


When we found the identities of the schools by other means, serious problems with the conclusions of the article were quickly revealed.

  • The 2008 paper was far from unique in this respect.
  • There are many papers that have had huge influences on K-12 mathematics curricula, and could not be independently verified because the authors refused to reveal their data.


In this article we describe how we were able to find the missing data for the 2008 paper. We discuss the huge difficulties they revealed, and point out the legal constraints that should make it very difficult for authors of such papers to legally withhold their data in the future.

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