圆锥的底面半径为3cm,侧面展开图是圆心角为120°的扇形,求这个圆锥的的全面积

圆锥的底面半径为3cm,侧面展开图是圆心角为120°的扇形,求这个圆锥的的全面积
圆锥的底面半径为3cm,侧面展开图是圆心角为120°的扇形,求这个圆锥的的全面积

圆锥的底面半径为3cm,侧面展开图是圆心角为120°的扇形,求这个圆锥的的全面积
扇形弧长=底面周长=6π
母线L：L*120π/180=6π
L=9cm
全面积S=πr²+πrL
=9π+27π
=36π

overthrown, Sun established the Republic of China government in Nanjing. Dudufu Nanjing, the provincial representatives held a meeting to discuss the calendar issue. At the signing of the "trip XIA, S...

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overthrown, Sun established the Republic of China government in Nanjing. Dudufu Nanjing, the provincial representatives held a meeting to discuss the calendar issue. At the signing of the "trip XIA, Shun ensure that the farming season from the western calendar, so they Statistics," the decision to use the Gregorian calendar, the calendar on January 1 custom "New Year", the end of the day of the Lunar New Year known as "Spring Festival", but has been formally named and promoted. September 27, 1949, the Chinese People's Political Consultative through the use of the first plenary session of "Annals of the Gregorian" calendar will be on January 1 as a "New Year's Day" is the beginning of the Lunar New Year will certainly entitled "Spring Festival", and that three-day Lunar New Year holiday, let people warmly celebrate the Lunar New Year.
In 2,000 years of history in the process, China's New Year customs experienced sprouting, stereotypes, fissile transition process of development.
Pre-Qin period, the New Year practices in its infancy stage. At this time of celebration activities mainly in the agricultural end of the year, to repay the gift of God and the "La Festival." "The Book of Songs July" recorded in the period of the Western Zhou Dynasty old at the turn of the New Year festive customs. Poems so-called "peer Andean enjoy wine, the lamb kill, Ji Gong Tang He said He statement of, Moshoumojiang" is that people will be dedicated to wine and lamb gods reward in the past year and God bless blessing. At this time of celebration activities because of the nobility of the country does not adopt the same calendar day and there is no uniform, Nongxian generally in the winter when it is the embryonic form of subsequent New Year customs.
New Year customs stereotypes in the Han Dynasty. After the end of the Warring States Period and the Qin Dynasty general social upheaval, the early Western Han Dynasty "to recuperate" policy, social production have been resumed and developed, stable social order and people's life goals high, a series of festive customs formed. "Tachu Calendar" after the implementation of long-term stability calendar, the end of the day as the date of the New Year, it has established. As a result, the various regions in the original Dongmochunchu different days at the Choushen, worship and celebration of the Lunar New Year will be gradually unified the end of the day to this day. With the development of society, from the Han Dynasty to the Northern and Southern Dynasties, the end of the day the custom of the South Korean activists packed growing, burning firecrackers for Zhaofu, Su Tu drink wine, Pu-year-old detainees and recreational activities such as Shangding have a New Year become China's first big festival .
New Year customs in the Tang Dynasty in fission. Tang is the era of ideological and cultural advances, but also frequent cultural exchanges both inside and outside of the times, New Year customs gradually from prayer, superstition, bustling addition to the mysterious atmosphere of liberation, transformed into entertainment, courtesy of festival. New Year's Day is no longer the firecrackers means Qugui evil spirits, and a joyous, jubilant way to celebrate the New Year by the focus to the entertainment of God, to the people their own entertainment games, and enjoy life. Therefore, it can be said, and only in the Tang Dynasty, the only truly celebrate the New Year, 100 million people celebrate the "Festival Liang."
New Year customs transition to the Ming and Qing Dynasties. This transition is mainly manifested in two aspects: First, etiquette, entertainment enhanced. People paid respects to each other in the New Year, the prestigious officials and others sent Mingtie each other, or, they Koubai; civilians also about "reciprocity", gift gifts, Betty each other. Second, entertainment and further strengthened. New Year period, playing the lion, dragon dance, acting, story tellers, stilt walkers, and other entertainment Hanchuan colorful, brilliant display. Beijingers Fair Yantian, Guangzhou people-goers, Suzhou people listen Hanshanshi bell, the people of Shanghai Chenghuangmiao…… travel around the unique entertainment activities, the endless variety of entertainment, dazzling. At that moment, the Chinese New Year customs will be perfect integration of traditional culture to become concentrated display of China's thousands of years of folk customs and culture Expo.
Over 2,000 years of history, the Chinese New Year customs prevalent in China Chek permeate everyone'sChinese New Year date, the dynasty not the same. Xia Dynasty scheduled in early January, the Shang Dynasty in early December, in early November for the Zhou dynasty, the Qin Dynasty in early October. Tachu to the first year of the Western Han Dynasty (104 BC), Han Wudi Sima Qian, who accepted the recommendations of the use of "Tachu calendar," and restore the Lunar XIA that, for the first month, living with the 24 Solar Terms of the calendar. Although later on the calendar Chinese dynasties have been modified, but still basically "Tachu calendar" a blueprint to XIA the Meng-Chun, living for the first month, the end of the day for New Year's Day, Yuanri, that is, the first day of the New Year.
named and promoted. September 27, 1949, the Chinese People's Political Consultative through the use of the first plenary session of "Annals of the Gregorian" calendar will be on January 1 as a "New Year's Day" is the beginning of the Lunar New Year will certainly entitled "Spring Festival", and that three-day Lunar New Year holiday, let people warmly celebrate the Lunar New Year.
In 2,000 years of history in the process, China's New Year customs experienced sprouting

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