30 résultats pour "circles"
- Circle I INTRODUCTION Circle Terms Terms that apply to circles include the center, radius, diameter, secant, and tangent.
- Degree I INTRODUCTION Degree, in trigonometry, arc equaling 1/360 of the circumference of a circle, or the central angle subtended by such an arc.
-
Geometry
I
INTRODUCTION
Geometry, branch of mathematics that deals with shapes and sizes.
Conic sections, a commonly studied topic of geometry, are two-dimensional curves created by slicing a plane through a three-dimensional hollow cone. A Euclid’s Postulates Euclid, who lived about 300 BC, realized that only a small number of postulates underlay the various geometric theorems known at the time. He determined that these theorems could be deduced from just five postulates. 1. A straight line may be drawn through any two given points. 2. A straight line may be drawn infinitely or be...
-
Plato
I
INTRODUCTION
Plato (428?
one of the individuals escapes from the cave into the light of day. With the aid of the sun, that person sees for the first time the real world and returns to the cave withthe message that the only things they have seen heretofore are shadows and appearances and that the real world awaits them if they are willing to struggle free oftheir bonds. The shadowy environment of the cave symbolizes for Plato the physical world of appearances. Escape into the sun-filled setting outside the cave symbolize...
-
Plato.
one of the individuals escapes from the cave into the light of day. With the aid of the sun, that person sees for the first time the real world and returns to the cave withthe message that the only things they have seen heretofore are shadows and appearances and that the real world awaits them if they are willing to struggle free oftheir bonds. The shadowy environment of the cave symbolizes for Plato the physical world of appearances. Escape into the sun-filled setting outside the cave symbolize...
-
History of Astronomy - astronomy.
Egypt, the Sun was directly overhead at noon. On the same date and time in Alexandria, Egypt, the Sun was about 7 degrees south of zenith. With simple geometryand knowledge of the distance between the two cities, he estimated the circumference of the Earth to be 250,000 stadia. (The stadium was a unit of length, derivedfrom the length of the racetrack in an ancient Greek stadium. We have an approximate idea of how big an ancient Greek stadium was, and based on that approximationEratosthenes was...
-
Map - Geography.
Often only southeast slopes are hachured or shaded, giving somewhat the effect of a bird's-eye view of the area illuminated by light from the northwest. Shadings orcarefully drawn hachures, neither of which give elevations, are more easily interpreted than contour lines and are sometimes used in conjunction with them for greaterclarity. IV MAP PROJECTIONS For the representation of the entire surface of the earth without any kind of distortion, a map must have a spherical surface; a map of this...
-
Dolphin (aquatic mammal) - biology.
Scientists have observed dolphins displaying three types of caregiving behaviors: standing by, excitement, and supporting. In standing-by behavior, dolphins remain inthe vicinity of an injured or ill companion without offering aid. In excitement behavior, dolphins swim swiftly in circles around an injured dolphin, responding aggressivelytoward threats to the injured animal. For instance, they may bite harpoon lines or charge boats that come too close to the animal. In supporting behavior, one or...
-
-
Sweden - country.
mi) and is Sweden’s second largest lake, after Vänern. The two lakes, together with several smaller lakes, rivers, and canals, form an internal water route called theGöta Canal. Built in the early 19th century, the Göta Canal extends for about 386 km (about 240 mi) and provides a scenic transportation link between the Baltic Sea,at Stockholm, and the Kattegat. Sweden’s other large lakes in the district include Mälaren, Hjälmaren, and the famously picturesque Siljan. D Climate Although one-seven...
-
Honey Bee - biology.
B Reproduction and Development The queen controls the sex of her offspring. When an egg passes from her ovary to her oviduct, the queen determines whether the egg is fertilized with sperm from thespermatheca. A fertilized egg develops into a female honey bee, either worker or queen, and an unfertilized egg becomes a male honey bee, or drone. The queen lays the eggs that will develop into more queens in specially constructed downward-pointing, peanut-shaped cells, in which the egg adheres to the...
-
Antarctica - Geography.
The maximum area of sea ice surrounding Antarctica each winter varies from year to year. A marked decline during the 1970s appears to have reversed in more recentdecades, except in the Antarctic Peninsula area. This area has lost almost 40 percent of its sea ice since the start of the 1980s. Sea ice is important to marine life. Krillfeed on algae that live under the sea ice and are released when the ice melts in spring and summer. In turn, many marine animals feed on krill. Emperor penguinsbreed...
-
Native American Architecture
I
INTRODUCTION
Native American Architecture, traditional architecture of the peoples of who lived in North America before Europeans arrived.
Mound Builders who resided in the area.John Elk III/Bruce Coleman, Inc. Another mound building culture, named Hopewell, also appears to have originated in Ohio but expanded west to Iowa, Kansas, and Oklahoma, south to Louisiana,Mississippi, and Alabama, east to Georgia and the Appalachian Mountains, and north to Wisconsin, Michigan, and lower Ontario in Canada. The Hopewell culture lastedfrom about 200 BC to 400 AD. Hopewell people built large, linear mounds to create enclosures in geometrical...
-
Arctic - geography.
B Rivers and Lakes Low precipitation is characteristic of the Arctic, so large and elaborate river and lake systems are rare. In many places, however, permafrost (permanently frozen subsoil)restricts the downward drainage of meltwater from snow, and the water accumulates on the surface as shallow lakes, ponds, and marshes. In addition, rivers from morehumid regions flow seaward across the dry Arctic terrain. Several large rivers are in the Russian Arctic, and the Mackenzie and Yukon rivers are...
-
From Bulfinch's Mythology: Druids - anthology.
Besides these two great annual festivals, the Druids were in the habit of observing the full moon, and especially the sixth day of the moon. On the latter they soughtthe Mistletoe, which grew on their favourite oaks, and to which, as well as to the oak itself, they ascribed a peculiar virtue and sacredness. The discovery of it was anoccasion of rejoicing and solemn worship. 'They call it,' says [1st-century Roman encyclopedist] Pliny [the Elder], 'by a word in their language, which means 'heal-a...
-
Native American Architecture.
B Relationship to the Universe and Nature A more profound difference between European American and Native American perceptions lay in how human beings saw themselves in relationship to the universe andin what they believed their responsibilities were to the natural world and to each other. Most European Americans saw themselves as separate from creation andadversaries of nature, ever struggling to conquer and subdue nature and force it to yield to their will. Native Americans saw themselves as...
-
Augustine
do what one knows one ought not to be doing, mark him off from ethicists of the classical Greek period. YetAugustine also preserves in his own thinking important strands of ancient Greek thought. Thus, for example, hisdevelopment of the doctrine of the Christian virtues includes an echo of Plato's idea of the unity of the virtues. Hisinsistence that 'ought' does not, in any straightforward way, imply 'can', distinguishes him, not only from hiscontemporary Pelagius, whom he helped brand...
-
-
Cleveland (Ohio) - geography.
Cleveland Children’s Museum. Also located in University Circle is Severance Hall, the home of the world-acclaimed Cleveland Orchestra. Nearby is the Cleveland PlayHouse, with three large, restored theaters and one of the largest non-profit professional theaters in the country. Downtown is Playhouse Square Center, with fourrecently restored theaters, home to the Cleveland Opera and the Great Lakes Theater Festival. On the waterfront is the Rock and Roll Hall of Fame and Museum,opened in 1995 and...
-
Venus (planet) - astronomy.
level winds circle the planet at 360 km/h (225 mph), making a complete rotation in only four days. These winds are said to super-rotate because they travel muchfaster than the rotation of the planet itself. These high-speed winds cover the planet completely, blowing toward the west at virtually every latitude from equator topole. The motions of descending probes, however, have shown that the bulk of Venus’s tremendously dense atmosphere, closer to the planet’s surface, is almoststagnant. From th...
-
USA - Iraq War - History.
B Making the Case for War B1 “Neoconservatives” and the Bush Doctrine Long before President George W. Bush took office in 2001, elements in or close to the Republican Party had called repeatedly for firmer U.S. steps against Iraq,including a war if necessary to force a regime change. One such group authored a white paper in 1996 called A Clean Break: A New Strategy for Securing the Realm , which was later sent to Prime Minister Benjamin Netanyahu, leader of Israel’s Likud Party. It advocated...
-
U.S.-Iraq War - U.S. History.
I
INTRODUCTION
U.S.-Iraq War, military action begun in
B Making the Case for War B1 “Neoconservatives” and the Bush Doctrine Long before President George W. Bush took office in 2001, elements in or close to the Republican Party had called repeatedly for firmer U.S. steps against Iraq,including a war if necessary to force a regime change. One such group authored a white paper in 1996 called A Clean Break: A New Strategy for Securing the Realm , which was later sent to Prime Minister Benjamin Netanyahu, leader of Israel’s Likud Party. It advocated...
- Tangent (geometry).
- Radian.
-
Stonehenge.
A Recent Excavations In 2006 excavations at Durrington Walls, about 3 km (less than 2 mi) from Stonehenge, uncovered a large settlement dating to 2600 or 2500 BC. The settlement consisted of wooden structures laid out in the same pattern as Stonehenge and, according to the archaeologists who conducted the excavations, probably housed theworkers who built Stonehenge. However, the remains of large amounts of pottery and animal bones found at the site suggest that it was a place of feasting, whic...
-
Stonehenge - History.
In 2006 excavations at Durrington Walls, about 3 km (less than 2 mi) from Stonehenge, uncovered a large settlement dating to 2600 or 2500 BC. The settlement consisted of wooden structures laid out in the same pattern as Stonehenge and, according to the archaeologists who conducted the excavations, probably housed theworkers who built Stonehenge. However, the remains of large amounts of pottery and animal bones found at the site suggest that it was a place of feasting, which maymean that it hous...
-
-
Indianapolis - geography.
nation to handle multiple railroad lines (thus the name “union”). Ringing the Mile Square are a number of historic districts such as Woodruff Place and Lockerbie Square. To the immediate northwest of downtown is Indiana Avenue, thehistoric center of the city’s black population. Some 6 km (4 mi) due north of Monument Circle is the North Meridian Street Historic District, a stretch of mansions built in the1920s and 1930s, including the Governor’s Residence. The district ends at the Central Canal,...
-
Oerter Wins Third Gold Medal.
Few expected Oerter to show up for the qualifying rounds. Nevertheless he did, with several parts of his 6-foot-4-inch, 270-pound body wrapped in tape, packed inice, and numbed with Novocain. After doffing his neck brace, he propelled the discus a miraculous 198 ft 7.5 in (60.5 m) in his first effort, achieving anotherOlympic record. Wrenched with pain, Oerter told a teammate before the start of the final round that his only chance to win was with a strong first throw. His initial effort, ho...
- Pi. Pi, Greek letter (p) used in mathematics as the symbol
-
From Bulfinch's Mythology: Ibycus - anthology.
The choristers, clad in black, bore in their fleshless hands torches blazing with a pitchy flame. Their cheeks were bloodless, and in place of hair writhing and swellingserpents curled around their brows. Forming a circle, these awful beings sang their hymns, rending the hearts of the guilty, and enchaining all their faculties. It roseand swelled, overpowering the sound of the instruments, stealing the judgment, palsying the heart, curdling the blood. 'Happy the man who keeps his heart pure...
-
Skiing.
Safety is very important to all skiers, and all Alpine resorts have a ski patrol. The ski patrol’s responsibility is to take care of injured skiers, to mark hazardous spots ontrails, to make sure that trails are in good condition before opening them, and, at times, to act as traffic police in congested areas. Skiers are also responsible for takingtheir own safety into consideration, as well as that of others. Anyone who participates in the sport should be aware of the Skier’s Responsibility Code...
-
Football.
C Special Teams Each team has players who enter the game during special plays such as kickoffs, field goals, punts, and returns. The kicker kicks off at the beginning of a game or half,and after his team has scored. The kicker also scores points for the offensive team by kicking the ball through the goalpost’s vertical posts, also known as the uprights;these scores are called field goals. When the offensive team must surrender the ball to the opponents, a punter comes in to kick the ball downfi...