Practise finding the area of shapes:

http://www.freewebtown.com/weddell/mw/shape/area/area.swf

Useful information on finding the area of rectangles:

http://www.bbc.co.uk/skillswise/numbers/measuring/perimeterareaandvolume/arearectangle/

A demonstration of the area and perimeter of the shape changing as you change the shape:

http://argyll.epsb.ca/jreed/math9/strand3/area_rectangles.htm

An excellent activity to help you work out the perimeter of shapes:

http://www.ngfl-cymru.org.uk/vtc/perimeter_sen/eng/Introduction/mainsession.htm

A revision of how to find both the perimeter and area of the shape:

http://www.bgfl.org/bgfl/custom/resources_ftp/client_ftp/ks2/maths/perimeter_and_area/index.html