- published: 04 Jun 2011
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In geometry, a square is a regular quadrilateral, which means that it has four equal sides and four equal angles (90-degree angles, or right angles). It can also be defined as a rectangle in which two adjacent sides have equal length. A square with vertices ABCD would be denoted ABCD.
The square is the n=2 case of the families of n-hypercubes and n-orthoplexes.
A square has Schläfli symbol {4}. A truncated square, t{4}, is an octagon, {8}. An alternated square, h{4}, is a digon, {2}.
A square is a special case of a rhombus (equal sides, opposite equal angles), a kite (two pairs of adjacent equal sides), a parallelogram (opposite sides parallel), a quadrilateral or tetragon (four-sided polygon), and a rectangle (opposite sides equal, right-angles) and therefore has all the properties of all these shapes, namely:
TR or tr may stand for:
Choice involves mentally making a decision: judging the merits of multiple options and selecting one or more of them. One can make a choice between imagined options ("what would I do if ...?") or between real options followed by the corresponding action. For example, a traveller might choose a route for a journey based on the preference of arriving at a given destination as soon as possible. The preferred (and therefore chosen) route can then follow from information such as the length of each of the possible routes, traffic conditions, etc. If the arrival at a choice includes more complex motivators, cognition, instinct and feeling can become more intertwined.
Simple choices might include what to eat for dinner or what to wear on a Saturday morning - choices that have relatively low-impact on the chooser's life overall. More complex choices might involve (for example) what candidate to vote for in an election, what profession to pursue, a life partner, etc. - choices based on multiple influences and having larger ramifications.
Barack Hussein Obama II (US i/bəˈrɑːk huːˈseɪn oʊˈbɑːmə/; born August 4, 1961) is an American politician serving as the 44th President of the United States, the first African American to hold the office. Born in Honolulu, Hawaii, Obama is a graduate of Columbia University and Harvard Law School, where he served as president of the Harvard Law Review. He was a community organizer in Chicago before earning his law degree. He worked as a civil rights attorney and taught constitutional law at University of Chicago Law School between 1992 and 2004. He served three terms representing the 13th District in the Illinois Senate from 1997 to 2004, and ran unsuccessfully in the Democratic primary for the United States House of Representatives in 2000 against incumbent Bobby Rush.
In 2004, Obama received national attention during his campaign to represent Illinois in the United States Senate with his victory in the March Democratic Party primary, his keynote address at the Democratic National Convention in July, and his election to the Senate in November. He began his presidential campaign in 2007 and, after a close primary campaign against Hillary Rodham Clinton in 2008, he won sufficient delegates in the Democratic Party primaries to receive the presidential nomination. He then defeated Republican nominee John McCain in the general election, and was inaugurated as president on January 20, 2009. Nine months after his inauguration, Obama was named the 2009 Nobel Peace Prize laureate.