![Question #2 of 'Properties of Parallelograms',... Find the values of AB and x when BC=26, CD=22, and DA=2x+12.](https://webarchive.library.unt.edu/web/20130216005922im_/http://www.free.ed.gov/images/resources/collected.jpg)
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![Riemann zeta function](https://webarchive.library.unt.edu/web/20130216005922im_/http://www.free.ed.gov/images/resources/0480.jpg)
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MathDL provides Java applets, interactive modules, and Flash presentations for studying...
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![Our solar system is a series of bubbles within bubbles -- plasma within magnetic fields separated from each other by huge, flowing sheets of electric currents.](https://webarchive.library.unt.edu/web/20130216005922im_/http://www.free.ed.gov/images/resources/physics-front.jpg)
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The Physics Front provides selected resources for teachers of high school physics. Hundreds of lessons...
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![Take a equilateral triangle, divide each side into 4 segments. Then connect the each vertex to division points on the opposite sides as you observe.](https://webarchive.library.unt.edu/web/20130216005922im_/http://www.free.ed.gov/images/resources/intermath.jpg)
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InterMath is designed to help middle school teachers deepen their understanding of math concepts...
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