题干

下面是两个可以自由转动的转盘,转动转盘,分别计算转盘停止后,指针落在红色区域的概率.
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答案(点此获取答案解析)

解:由图可以看出,在第一个转盘内,红色区域的圆心角是90°,因此可以算得指针落在红色区域的概率是 90360
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1
4
;在第二个转盘内,红色区域的圆心角是135°,因此可以算得指针落在红色区域的概率是

同类题4

信息归纳:阅读下文,根据所提供的信息,完成下列表格。

Stop Phubbing (别当低头族)

     Last month, Justin Valdez, a college student was shot in subway in San Francisco, the U.S. The surveillance(监控) video showed that before Justin was killed, the killer pulled out the gun several times, and even wiped his nose with it. However, nobody noticed the killer. The surrounding passengers all focused on their mobile phones.

     We may see the same scene everywhere in the life: in subway, restaurants. Elevators, roads, people are watching their mobile phones. From family reunion to date with a friend, people can't stop checking their WeChat, Facebook on the mobile phone and snubbing(无视) the persons in front completely. Not only the young people, but also the olds and the kids.

     “Phubbing” is a new word which comes from the words “phone” and “snub”. It means the habit of snubbing someone in favor of(只顾着) a mobile phone. The word “phubbing” was included in the Australian National Dictionary in 2012. So we can see phubbing is spreading globlly.

     Phubbing seems innocuous(无害的); however, it disturbs our life. Stop posting photos. Let's put down the mobile phone and enjoy the real taste of food and the warmth of interpersonal(人与人之间) communication.

Information Card

The place where Justin Valdez comes from

____

The things that the passengers focused on when Justin Valdez was shot

____

The meaning of phubbing

____

The time when the word “phubbing” was included in the Australian National Dictionary

____

The reason why the writer asks us to stop posting photos

____