<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<http://schema.org/WebSite>
<https://www.wyzant.com/resources/answers/39323/what_is_the_perimeter_of_a_octogon_if_its_area_is_20_72cm_and_its_apothem_is_2_5cm>