A page of the Numeropedia - the Special Encyclopedia of Numbers
The isosceles triangle of sides 12-12-17 (inches) at the top of the home plate (whose shape is a non-regular pentagon) in baseball is not quite a right triangle as specified, since 122+122 = 288 < 172 = 289. Its largest angle is an obtuse angle of 90.2o.
The 12th man is usually referred to the “fans” of an American football team.
The regular playing time of an NBA (National Basketball Association) game is 48 minutes, in four 12-minute quarters.
For a penalty kick in a soccer game, the ball is centered at 12 yards (11 meters) from the goal line.
The official total number of players (starting and reserved) for a professional basketball team.
The perfect score in a bowling game is 300, for 12 consecutive strikes.