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
Straight from the Heart (Patrice Rushen album) "Straight from the Heart" a "C+" and said that he prefers side one's "dancy vamp" over the songwriting on side two by Rushen, whom he called a fashionable "ingenue". In a retrospective review, AllMusic's Andy Kellman gave it four out of five stars and called it "an early-'80s jazz-pop-R&B synthesis as durable and pleasing as any other". In 2018, Pitchfork ranked Straight From the Heart #194 on its list of the 200 Greatest Albums of the 1980s. Straight from the Heart (Patrice Rushen album) Straight from the Heart is the seventh studio album by American recording artist Patrice Rushen, released