Đa giác đều n đỉnh và nội tiếp đường tròn bán kính R có diện tích là

A. 1 2 n R 2 sin 360 n °

B. 1 2 n R 2 cos 360 n °

C. n R 2 sin 360 n °

D. n R 2 cos 360 n °

Fill in each numbered blank with one suitable word or phrase.

Silicon Valley is (1) _______ to hundreds of technology companies, so it comes as no surprise that San Jose has partnered with technological giant Intel to transform itself (2) _______ a smart city. San Jose and Intel will work (3) _______ to further the city's Green Vision initiative - a 15-year plan for economic growth, and improve (4) _______ which it launched in 2007. Intel expects to help San Jose create 25,000 clean-tech jobs, drive economic growth, and improve the city's environmental (5) _______. To achieve this (6) _______, Intel will work with the city to track real-time data on air quality, noise pollution, traffic flow, and other environmental and (7) _______concerns which it will then use to encourage (8) _______to reduce emissions by using public transportation or bicycles to get to work or school. Smart cities may sound like something of the distant future (9)_______ many people thought the same thing about smartphones and smart homes. Up to now, over 70 percent of American adults have owned a smartphone and 1.9 billion smart home devices have been installed.   If smart cities are (10) _______like these other smart innovations, we will see them appear in our communities sooner rather than later.

Question 1:

A. home

B. house

C. shelter

D. Housing