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 Again" and the flute section in "There Is a Light That Never Goes Out" (originally written as a guitar part) are based on C# minor arpeggio figure. The song features an ascending F#m–A–B chord sequence that guitarist Johnny Marr took from the Rolling Stones cover of Marvin Gaye's "Hitch Hike". Marr said in 1993 that he included the figure as an "in-joke" to determine if the music press would attribute the inspiration for the part to "There She Goes Again" by the Velvet Underground, who he contended "stole" the figure from "Hitch Hike". Marr commented, "I knew I was smarter