Group 1:
http://www.bgfl.org/bgfl/custom/resources_ftp/client_ftp/ks2/maths/perimeter_and_area/index.html
(Choose Perimeter Level 3, Then Area Level 2)
http://www.ngfl-cymru.org.uk/vtc/perimeter_sen/eng/Introduction/mainsession.htm (Level 2)
http://www.thatquiz.org/tq-A/math/triangle/(Level 10)
http://www.ixl.com/math/grade-5/area-and-perimeter-word-problems
Group 2:
(Choose Perimeter Level 2, Then Area Level 1)
http://www.mathplayground.com/area_perimeter.html
http://www.thatquiz.org/tq-A/math/triangle/(Level 5)
Group 3:
http://www.henryanker.com/Math/Geometry/Perimeter_Set_03.swfhttp://www.sadlier-oxford.com/math/enrichment/gr1/ch9/0109a.htm
(Choose Perimeter Level 1 Rectangle, Then Perimeter Level 1 Triangle, Then Area Level 1)
http://www.ngfl-cymru.org.uk/vtc/perimeter_sen/eng/Introduction/mainsession.htm(Level 1)
http://www.thatquiz.org/tq-A/math/triangle/(Level 3)