Circle of stars all EU leaders as the official emblem of the European Communities, and in 1993 inherited by the successor organisation, the European Union. All European institutions now use an emblem of their own. The Zodiac is an ancient "circle of stars" where some stars are symbolically combined into 12 Star signs also known as constellations. The etymology of the term Zodiac comes from the Latin zōdiacus, from the Greek ζῳδιακός [κύκλος], meaning "[circle] of animals", derived from ζῴδιον, the diminutive of ζῷον "animal". The Crown of Immortality is a separate and earlier motif (and metaphor) which also uses a circle of
Area of a circle Area of a circle In geometry, the area enclosed by a circle of radius is . Here the Greek letter represents a constant, approximately equal to 3.14159, which is equal to the ratio of the circumference of any circle to its diameter. One method of deriving this formula, which originated with Archimedes, involves viewing the circle as the limit of a sequence of regular polygons. The area of a regular polygon is half its perimeter multiplied by the distance from its center to its sides, and the corresponding formula (that the area is half the perimeter times the radius, i.e.