Ethno. Pixar in a box: New on Khan Academy. Scientists Discover 15th Convex Pentagon Able To Tile A Plane. Consider the ceramic on the floor beneath you.

Those squares or rectangles tile the plane. That's a mathematical term, and finding a new shape that covers a flat surface using only exact copies of that one shape without overlapping or leaving any gaps is a mathematical challenge. All triangles can tile the plane, all quadrangles, too. But only 14 pentagons - five-sided shapes - could do it. Or so we thought, to the extent that we thought about this at all. Welcome back to the program. JULIE REHMEYER: It's my pleasure, Robert, happy to talk to you. SIEGEL: How big a deal this is? REHMEYER: It's exciting. SIEGEL: Who found this new pentagon? REHMEYER: Three mathematicians at the University of Washington - Casey Mann, Jennifer McLoud and David Von Derau. SIEGEL: And there have been many searches for these geometric shapes over the decades?

Recreational Math. Cycloid Optical Illusion Will Boggle Your Mind. Optical illusions typically prey on your mind’s ability to fill in blanks in the visual stimulus it is receiving.

Sometimes this can be so strong, your mind continues to be tricked even after it has been explained. Case in point: this video from brusspup, purveyor of mind-melting illusions. The video looks like a wheel made out of eight white circles is rolling around inside of a large, red circle. That’s not what is actually happening, as the video will explain: I don’t know about you, but even after it was explained and the lines were taken away, my brain still wanted to see it as a rolling wheel. So how does this illusion actually work? The entire principle is based on cycloids; half circle shapes that are created by a fixed point on the rim of a circle. Image credit: Zorgit, via WikiMedia Commons Based off of this principle, the curved line can be represented linearly. Math is really damn cool sometimes. [Hat tip and eternal admiration to: Phil Plait, Slate]

Matematicas Visuales. In MatematicasVisuales you will find visual expositions of mathematical concepts.

MatematicasVisuales intends to complement the work initiated by artiludios , a site with games, puzzles and mathematical curiosities . Reading Miguel de Guzmán I found a demonstration of the line of Simpson and the Steiner Deltoid . It serves as an introduction to the geometry section. The concept of function and its graphical representation are a key concept and we dedicate special attention to it in the analysis section. Geometric representation of the complex numbers facilitates its visualization. Thinking in who have to start learning probability we have this section about this subject. In the history section we approach mathematics through its history. Miguel Cardil made the design of matematicasvisuales.com. The contents of MatematicasVisuales has been developed by Roberto Cardil .

CR Algebra Review.

Free Simulation and Modeling in Your Browser. Algebra Tiles. Virtual Manipulatives. Print Free Graph Paper. Dy/dan » Algebra: The Supplement. Differential Equations. Project MATHEMATICS! Mathematical Formula Tables. Making Math and Science Connections. Fill-It-In Outline Mathematics.

Free Mathematics Resources OnLine. What about free graphing and algebra on your mobile phone?

XCalc is a free Java Applet which offers a graphing calculator for any mobile phone which runs Java (which is nearly all of them now!) Think about the possibilities for classes that do not yet have access to graphing calculators! While limited (it does not yet have a trace facility) it DOES offer 2d and 3d graphing which is quite fast and powerful. Well worth a play! Now, combine that with quite a useful algebraic workpad that allows you to define variables and formulas and evaluate these.

Mathematics Assessment. Authentic Assessment in Mathematics Home Page. The Geometry Forum Summer '94 Workshop at Swarthmore College, Swarthmore, PA.

The goal of this project was to collect and organize available INTERNET resources on Authentic Mathematical Assessment applicable to Secondary Schools. What is it? Are there examples? Where can I find additional information? Group Project of:Pat Daley(Fairfield High School, Fairfield, CT: PDaley@Fair1.Fairfield.edu ); Mike Diamond (Pinewood Prep School, Summerville, SC: DiamondM@Citadel.edu); Saundra "Sandi" Handy (Mathematics/Science Demonstration Center, Washington DC: MSDC/Backus@DCNET.mste.org)Howard McKenzie (Essex Catholic High School, East Orange, NJ: HMckeRGI@Delphi.com ); Table of Contents General Information about Assessment Case Study Examples and Lesson Plans Software Listing Bibliography and Alternate Resources Completed by the tireless efforts of Mike Diamondwith little assistance from his sleeping partners.

MacTutor History of Mathematics. Sage: Open Source Mathematics Software. Jim Loy's Mathematics Page. Go to my home page Participate in The Most Pleasing Rectangle Web Poll which recently moved to jimloy.com. "He must be a 'practical' man who can see no poetry in mathematics. " - W.