The 78 (number) reference article from the English Wikipedia on 24-Apr-2004 (provided by Fixed Reference: snapshots of Wikipedia from wikipedia.org)

78 (number)

78 is the natural number following 77 and followed by 79.

List of numbers — Integers << 70 71 72 73 74 75 76 77 78 79 >>
Cardinal	seventy-eight
Ordinal	78th (seventy-eighth)
Factorization
Divisors	2, 3, 6, 13, 26, 39
Roman numeral	LXXVIII
Binary	1001110
Hexadecimal	4E

In mathematics

Seventy-eight is a triangular number, and its factorization makes it a sphenic number.

Karl A. Dahlke proved in 1989 that 78 heptominoss of this shape ( ), at a minimum, are required to fill a rectangle.

In other fields

Seventy-eight is also:

• The atomic number of platinum.
• The designation of Interstate 78, a freeway that runs from Pennsylvania to New York.
• In reference to analogue disc records, 78 refers those meant to be spun at 78 revolutions per minute. Compare: LP, 33 and 45.
• A standard Tarot deck containing the 22 cards of the major arcana (including the fool) and the 56 cards of the minor arcana make up 78 cards.
• The total number of gifts in the song The Twelve Days of Christmas (since 78 is the 12th triangular number).
• The year AD 78, 78 BC, or 1978.

This is the "78 (number)" reference article from the English Wikipedia. All text is available under the terms of the GNU Free Documentation License. See also our Disclaimer.