When the second floor was built in 1178, the tower started to lean. This was because it had a small three-meter foundation in soft soil. The design of this tower was bad from the beginning. Construction was stopped for almost 100 years because the people of Pisa were often at war with Genoa, Lucca, and Florence.
There is an old story that Galileo Galilei used the Tower for a physics experiment.
Tower
A tower is a tall structure. Towers are different from buildings because people do not live in them. Many castles have towers. Today, towers are very tall. Some things they are used for are to send radio signals, for observation, or to hold up bridges.
Tel Aviv
The city of Tel Aviv-Yafo (;  ) is a municipality in Israel, often just called Tel Aviv. It is Israel's second largest city and main commercial, financial, and industrial center. It is on the eastern shore of the Mediterranean Sea.
In 2018, 451,523 people lived in the city of Tel Aviv. Tel Aviv is a part of an area of cities called Gush Dan. About 3,850,000 people live in this urban area.
The city calls itself Israel's capital of culture, economy and trade.
In 1909, Jewish people started building Tel Aviv northeast of Jaffa. Tel Aviv was part of Jaffa at first, but it became a separate town in 1921. Tel Aviv grew quickly as Jewish immigrants arrived, mainly from Europe.
between the years 1925-1929 the Scottish city planner Sir Patrick Geddes was design the first city plan for the tel aviv.
in the early 1930s the area of the Yarkon River mouth area has began to develop with the opening of the international trade fair - the "Orient Fair" and the opening of the "Tel Aviv Port" beside him. from the other side of the Yarkon River was built the Reading Power Station and the Sde Dov Airport.
It was Israel's first capital when the nation was established in 1948. The capital was moved to Jerusalem in 1949, but the Israeli Ministry of Defense and many foreign embassies stayed in Tel Aviv. Most Israeli government departments have offices in Tel Aviv.
In 1950, Tel Aviv and Jaffa (called "Yafo" in Hebrew) joined to into the city of Tel Aviv-Yafo. Tel Aviv-Yafo is the official name of the city, but it is almost always called Tel Aviv.
Tel Aviv continued to grow quickly in the 1950s and 1960s. The fast growth of the Tel Aviv area caused problems such as air pollution, slums, and traffic that took until the 2000s to fix. Most of the people of Tel Aviv live in apartment buildings.
During the Persian Gulf War of 1991, Iraq fired about 25 missiles toward Tel Aviv. Several missiles and falling debris struck residential areas in or around Tel Aviv. Two people were killed, and about 7,500 apartments were damaged.
The cultural center of Tel Aviv is a downtown intersection of streets at Dizengoff Circle. Fashionable shops and sidewalk cafes line the nearby streets. The 37-story Shalom Tower is in the city's financial district, several blocks south of Dizengoff Circle. It is the tallest building in Israel. The southwestern part of the city was once the separate town of Jaffa. Jaffa, an ancient port from Biblical times, has many historic place that have been restored by archaeologists. Jaffa also has many art galleries, cafes, restaurants, and nightclubs.
The Israeli opera, and Habima Theater, Israel's national theater, was are in Tel Aviv.
Tel Aviv is home to a number of dance centers and companies. The Batsheva Dance Company, a contemporary dance group, as well as the Bat-Dor Dance Company and the Israel Ballet are headquartered in Tel Aviv. Tel Aviv's center for modern and classical dance is the Suzanne Dellal Center.
Museums in Tel Aviv include Haaretz Museum and the Tel Aviv Art Museum.
Tel Aviv University is one of the city's several institutions of higher learning. Bar Ilan University is in Ramat Gan, a suburb of the city.
Tel Aviv is the Gay capital of Israel.
The Tel Aviv area is Israel's main manufacturing district. About half of the nation's business companies are in the area. Their products include computer software, electronic equipment, machine tools, building materials, chemicals, clothing, and processed foods. The city is also the nation's main center for banking, publishing, and trade and the home of the Tel Aviv Stock Exchange. Abu Kabir Forensic Institute, the nation's only forensics institute, is located there.
Tel Aviv has a partnership with Los Angeles (), and is twinned with:
Trigonometry
Trigonometry (from the Greek "trigonon" = three angles and "metron" = measure) is a part of elementary mathematics dealing with angles, triangles and trigonometric functions such as sine (abbreviated sin), cosine (abbreviated cos) and tangent (abbreviated tan). It has some connection to geometry, although there is disagreement on exactly what that connection is; for some, trigonometry is just a section of geometry.
Trigonometry uses a large number of specific words to describe parts of a triangle. Some of the definitions in trigonometry are:
There are three main trigonometric ratios for right triangles, and three reciprocals of those ratios, making up a total of 6 ratios. They are:
The reciprocals of these ratios are:
Cosecant (cosec) - The cosecant of an angle is equal to the formula_4 or formula_5.
Secant (sec) - The secant of an angle is equal to the formula_6 or formula_7.
Cotangent (cot) - The cotangent of an angle is equal to the formula_8 or formula_9.
Students often use a mnemonic to remember this relationship. The "sine", "cosine", and "tangent" ratios in a right triangle can be remembered by representing them as strings of letters, such as SOH-CAH-TOA:
With the sines and cosines, one can answer virtually all questions about triangles. This is called "solving" the triangle. One can work out the remaining angles and sides of any triangle, as soon as two sides and their included angle or two angles and a side or three sides are known. These laws are useful in all branches of geometry, since "every polygon may be described as a combination of triangles".
Trigonometry is also vital in surveying, in vector analysis, and in the study of periodic functions. It developed from a need to compute angles and distances in fields such as astronomy, mapmaking, surveying, and artillery range finding.
There is also such a thing as spherical trigonometry, which deals with spherical geometry. This is used for calculations in astronomy, geodesy and navigation.
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Monotheism
Monotheism is the belief in only one god, rather than two or more, which would be polytheism such as Ancient Greece, Ancient Rome, Ancient Egypt and partly Hinduism. Many religions are monotheistic, such as Judaism, Christianity, Islam, Baha'i Faith, Sikhism, Eckankar, Zoroastrianism, Cao Dai and Tenrikyo. Some pagan and neo-pagan religions are also monotheistic. Deism is the belief that a higher being like god exists, but rejects the belief in many gods, revelation, religions, rituals, sacred books (like the Bible or Quran), prophets (like Jesus or Muhammad), etc. Judaism and Zoroastrianism are thought to be the oldest living monotheistic religions.
Polytheism
Polytheism means believing in many gods. A person that believes in polytheism is called a polytheist. A religion with polytheism can be called a polytheistic religion.
Polytheism is well documented in historical religions of classical antiquity, especially those of ancient Greeks and Romans. Other ancient people who were polytheists include German pagans, Ancient Egyptians, the Celts and the Norse.
There are various polytheistic religions practiced today. Examples include Sanamahism (Meitei paganism), Shinto, Chinese folk religion, Thelma, Wicca, Druidism, Taoism, Asatru and Candomblé.
Usually, a polytheistic religion has a set of stories about the gods. This is called mythology.
The opposite of polytheism is monotheism, which is the belief in only one god, practiced by the monotheistic religions of Judaism, Christianity, Islam, Sikhism, etc.
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