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 home") is quoted in the song. According to Goddard, an earlier version lacked some of the finished version's ambiguity, culminating in the line "There is a light "in your eyes" and it never goes out". Due to a dispute between the Smiths and its record label Rough Trade Records after the group completed "The Queen Is Dead", nine months passed after the release of "The Boy with the Thorn in His Side" before the group issued another single. Once the matter was resolved, Rough Trade owner Geoff Travis felt that "There Is a Light That Never Goes Out" should be