1 This implies that the other two sides are of equal length, and that the diagonals are of equal length. 2  An alternative definition is: a quadrilateral with an axis of symmetry bisecting one pair of opposite sides. 3  Trapezium (NAm.): no sides are parallel.
An enumeration date commonly refers to the official or control date set for a particular enumeration event such as a census. The official enumeration date may vary from one enumeration to the next. The enumeration date is a control function for collecting data over a broad space of time. All data collected is based on its validity as of a single date, no matter what date the information is taken within the enumeration period.
To Excel, a date is simply a number. More precisely, a date is a serial number that represents the number of days since the fictitious date of January 0, 1900. A serial number of 1 corresponds to January 1, 1900; a serial number of 2 corresponds to January 2, 1900, and so on.