Tennis is played on a rectangular flat surface, usually of grass, clay or hard material. The dimensions of a tennis court are defined and regulated by the International Tennis Federation (ITF) governing body and are written down in the annual 'Rules of Tennis' document. The court is 78 feet (23.77 metres) long. Its width is 27 feet (8.23 metres) for singles matches and 36 feet (10.97 metres) for doubles matches. The service line is 21 feet (6.40 metres) from the net. Additional clear space around the court is needed in order for players to reach overrun balls for a total of 60 feet (18 metres) wide and 120 feet (37 metres) long.

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