Circle of latitude can be calculated by a common sine or cosine function. The 60th parallel north or south is half as long as the Equator (disregarding Earth's minor flattening by 0.3%). A circle of latitude is perpendicular to all meridians. The latitude of the circle is approximately the angle between the Equator and the circle, with the angle's vertex at Earth's centre. The equator is at 0°, and the North Pole and South Pole are at 90° north and 90° south, respectively. The Equator is the longest circle of latitude and is the only circle of latitude which also is a great
The Last Dog on Earth appeal to teen readers. "The Last Dog on Earth" was included in the "What Ails You?" category, comprising literature "about how diseases, disorders, and other general health related symptoms affect our lives". In a 2005 interview, Daniel Ehrenhaft mentioned that a school in Chicago created an extracurricular activity wherein "kids designed games and gadgets", having been inspired by Logan's hobby of inventing devices. "The Last Dog on Earth" has received mixed reception from critics, who have praised the plot, but criticized the heavy use of coincidences to advance the plot. "Kirkus Reviews" commented that "happenstance plays a large role in