试题与答案

一个圆柱体的侧面积是942cm2，体积是2355cm3，它的底面积是______

来源：www.tikuol.com
题型：填空题

题目：

一个圆柱体的侧面积是 942cm2，体积是 2355cm3，它的底面积是______ cm2．

答案：

根据题干分析可得：

圆柱的底面半径：2355÷（942÷2），

=2355÷471，

=5（厘米），

3.14×52=78.5（平方厘米），

答：底面积是78.5平方厘米．

故答案为：78.5．

考点：圆柱的表面积圆柱的体积
试题推荐
题型：单项选择题

(三)

Believe it or not, optical illusion can cut highway crashes.

Japan is a case in point. It has reduced automobile crashes on some roads by nearly 75 percent using a simple optical illusion. But stripes, called chevrons, painted on the roads make drivers think that they are driving faster than: they really are, and thus drivers slow down.

Now the American Automobile Association Foundation for Traffic Safety in Washington D. C. is planning to repeat Japan’s success. Starting next year, the foundation will paint chevrons and other patterns of stripes on selected roads around the country to test how well the patterns reduce highway crashes.

Excessive(too great) speed plays a major role in as much as one fifth of all fatal traffic accidents, according to the foundation. To help reduce those accidents, the foundation will conduct its tests in areas where speed-related hazards(danger) are the greatest curves, exit slopes, traffic circles, and bridges.

Some studies suggest that straight, horizontal bars painted across roads can initially cut the average speed of drivers in half. However, traffic often returns to full speed within months as drivers become used to seeing the painted bars.

Chevrons, scientists say, not only give drivers the impression that they are driving faster than they really are but also make a lane appear to be narrower. The result is a longer lasting reduction in highway speed and the number of traffic accidents.

The advantage of chevrons over straight, horizontal bars is that the former（）.

A．can keep drivers awake

B．can cut road accidents in half

C．will look more attractive

D．will have a longer effect on drivers
查看答案
微信公众账号搜索答案