Pentagon Pentagon In geometry, a pentagon (from the Greek πέντε "pente" and γωνία "gonia", meaning "five" and "angle") is any five-sided polygon or 5-gon. The sum of the internal angles in a simple pentagon is 540°. A pentagon may be simple or self-intersecting. A self-intersecting "regular pentagon" (or "star pentagon") is called a pentagram. A "regular pentagon" has Schläfli symbol {5} and interior angles are 108°. A "regular pentagon" has five lines of reflectional symmetry, and rotational symmetry of order 5 (through 72°, 144°, 216° and 288°). The diagonals of a convex regular pentagon are in the golden ratio to its
The Sum of All Fears The Sum of All Fears The Sum of All Fears is a political thriller novel, written by Tom Clancy and released on August 14, 1991. Serving as the sequel to "Clear and Present Danger" (1989), main character Jack Ryan, who is now the Deputy Director of Central Intelligence, tries to stop a crisis concerning the Middle East peace process where Palestinian and former East German terrorists conspire to bring the United States and Soviet Union into nuclear war. It debuted at number one on the New York Times bestseller list. A film adaptation, which is a reboot of the Jack