Given this paragraph about the dimensions of a volleyball court, what is the area of one half of a volleyball court with an explanation of the math behind the calculation.

A volleyball court is 9 m × 18 m (29.5 ft × 59.1 ft), divided into equal square halves by a net with a width of one meter (39.4 in).[18] The top of the net is 2.43 m (7 ft 11+11⁄16 in) above the centre of the court for men's competition, and 2.24 m (7 ft 4+3⁄16 in) for women's competition, varied for veterans and junior competitions.

The area of one half of a volleyball court is 81 square meters. The total area of the court is 162 square meters (9 m x 18 m). It is divided into two equal square halves of 81 square meters each (9 m x 9 m).