Perimeter and Circumference
Perimeter
http://www.mathvids.com/lesson/mathhelp/487-finding-perimeter
Learn about finding the perimeter of shapes.
Perimeter
http://www.5min.com/Video/How-to-Calculate-a-Perimeter-285016066
Learn about finding the perimeter of polygons and quadrilaterals.
Radius, Diameter, Circumference
http://www.khanacademy.org/video/circles--radius--diameter-and-circumference?playlist=Geometry
Definitions of circle geometry terms. Learn and practice finding the circumference of circles.
Circumference
http://www.ehow.co.uk/video_4755243_find-perimeter-circle.html
Learn about finding the circumference of circles.
Circumference
http://www.youtube.com/watch?v=ORN7qLkuKOk
Learn about finding circumference using both radius and diameter.