Phi and the Golden Section in Architecture

Phi (Phi ), the Golden Section, has been used by mankind for centuries in architecture

Its use started as early as with the Egyptians in the design of the pyramids.  When the basic phi relationships are used to create a right triangle, it forms the dimensions of the great pyramids of Egypt, with the geometry shown below creating an angle of 51.83 degrees, the cosine of which is phi, or 0.618.

The Greeks knew it as the "dividing a line in the extreme and mean ratio" and used it extensively for beauty and balance in the design of the Parthenon and other architecture:

It was used it in the design of Notre Dame in Paris, which was built in the 1163 and 1250.

Renaissance artists of the 1500's in the time of Leonardo Da Vinci knew it as the Divine Proportion.  In India, it was used in the construction of the Taj Mahal, which was completed in 1648.  Click on photos below for enlarged image.

Thanks go to Moein Danesh for the contribution of information on the Taj Mahal.

Its use continues in modern architecture, as illustrated in the United Nations building:

The CN Tower in Toronto, the tallest tower and freestanding structure in the world, has contains the golden ratio in its design. The ratio of observation deck at 342 meters to the total height of 553.33 is 0.618 or phi, the reciprocal of Phi!

Thanks go to John Owen for his contribution of this information on the CN Tower