Difference of Two Squares (1) 平方差公式(一)
Proof without words shared by alexchik.
http://www.geogebratube.org/material/show/id/17333 (Download GeoGebra file)
Modified slightly.
http://www.geogebratube.org/material/show/id/17379 (Download GeoGebra file)
Proof without words shared by alexchik.
http://www.geogebratube.org/material/show/id/17333 (Download GeoGebra file)
Modified slightly.
http://www.geogebratube.org/material/show/id/17379 (Download GeoGebra file)