[Test.4] A point is said to divide a line segment in extreme and mean ritio, of in golden section, when the longer of the two segments formed is the mean proportional between the shorter segment to the longer segment is called the

golden tatio. The Pythagoreans showed consederable inferest in the golden scction and the golden ratio.
The wymbol of the Pythagorean brotherhood was the pentagram, of 5_pointed_star, formed by the 5 diagonals of a regular pentagon.
Show that the golden ratio is (¡î5-1)/2.