Check Out This Incredible Math Trick

[Econometricia]

Sorry if this has been posted. Thought it was cool!
http://www.wimp.com/crazymath/

 

[Integral]

Bit different version of a old rube.

For the created shape to be a rectangle you need to have the slopes of the red and green triangles (3/8) be equal to the slope of the angle of the other 2 shapes (2/5).

Since .4 <> .375 that is not a rectangle and you cannot get the area by multiplying sides.

 

[HallsofIvy]

But still amusing!

 

[The Chaz]

Bit different version of a old rube.

For the created shape to be a rectangle you need to have the slopes of the red and green triangles (3/8) be equal to the slope of the angle of the other 2 shapes (2/5).

Since .4 <> .375 that is not a rectangle and you cannot get the area by multiplying sides.

So is it safe to say that in the 5x13 "rectangle", there is a triangle of area ONE unit with a vertex in the top right corner and two vertices near the bottom left corner?

edit...
No, that can't be right, since the slope changes from 3/8 to 2/5...
So vertices:
1) top right corner (13, 5)
2) at "point" (5,2)
3) bottom left corner (0,0)