Enter two numbers for [math]a[/math] and [math]b[/math]. Click on segments [math]a[/math], [math]b[/math] and [math](a+b)[/math] to form [math]a^2[/math], [math]b^2[/math] and [math](a+b)^2[/math]. Drag the red and the blue square over the orange square. Is it true that [math]a^2+b^2=(a+b)^2[/math]? What has to be added to the area [math]a^2+b^2[/math] to make it equal to the area [math](a+b)^2[/math] of the orange square?