Circle a triangle whose base has the length of the circle's circumference and whose height equals the circle's radius, which comes to multiplied by the radius squared: Equivalently, denoting diameter by "d", that is, approximately 79% of the circumscribing square (whose side is of length "d"). The circle is the plane curve enclosing the maximum area for a given arc length. This relates the circle to a problem in the calculus of variations, namely the isoperimetric inequality. Equation of a circle<br> In an "x"–"y" Cartesian coordinate system, the circle with centre coordinates ("a", "b") and radius "r" is the set of
There Is a Light That Never Goes Out from the Smiths' masterpiece third album, "The Queen Is Dead"." In 2014, "NME" listed "There Is a Light That Never Goes Out" as the 12th greatest song of all time. The website Acclaimed Music lists it as the 78th most acclaimed song of all time, and the 8th most acclaimed song of the 1980s. There is a chapter in Irvine Welsh's novel "Trainspotting" named after this song, which mentions its title directly. The song appears on the soundtrack to "(500) Days of Summer"; in the film, it is used to bring the main characters together. The song has been covered