Where is the golden ratio used?

It is used in nature all the time. Buds on plant stalks sprout using the Golden Ratio.

When architects use the Golden ratio to design a building , the building looks good, and feels good. The Parthenon on the Acropolis in Athens, Greece is such a building.

Good artist s often unconciously use the Golden Ratio ; the focus of a painting is never in the centre of the canvas, but at the golden ratio.

The ratio is 1: 1.618....

or (phi) = (1 + sqrt(5)) / 2 it is an Irrational number.

It also goes by the names , Golden Number, Devine Section, God's Number, etc.,

Have a look in Wikioedia under 'Golden Ratio'.