Wtf are you talking about... a animal doesn't have the right to piss in public?? I really hope you did drop a /s. I'm going to assume you did, because this is not reddit etc...
To get the flat length of a circle multiply it by pi(3.1415). The diamtere is the length from one side of a circle to the other. A radius is length of a circles size from center to outer edge. A radius is half the size of a diameter.