Whitchurch, Amy. "The Fence or the Carpet: Understanding Perimeter and Area". OER Commons. Institute for the Study of Knowledge Management in Education, 25 Apr. 2014. Web. 03 Jun. 2020. <https://www.oercommons.org/authoring/5500-the-fence-or-the-carpet-understanding-perimeter-an>.
Whitchurch, A. (2014, April 25). The Fence or the Carpet: Understanding Perimeter and Area. OER Commons. Retrieved June 03, 2020, from https://www.oercommons.org/authoring/5500-the-fence-or-the-carpet-understanding-perimeter-an.