Rectangles+and+Circles

Is a square a rectangle?

http://nrich.maths.org/public/viewer.php?obj_id=191

cracked right angles.

http://mathworld.wolfram.com/RightAngle.html

2d shapes

http://www.bgfl.org/bgfl/custom/resources_ftp/client_ftp/ks2/maths/3d/shapes.swf

interactive video explaining trapezoid, parallelogram, rectangle, and square.

http://my.hrw.com/math06_07/nsmedia/homework_help/msm2/msm2_ch08_07_homeworkhelp.html

Extra Practice

http://quizzer.eduplace.com/cgi-bin/quizzer2.cgi?ID=hmm07_ep/gr3/1504&GRADE=3&UNIT=6&START_QUIZ=1