費費 07-42

[clelia]

A tunnel is a semicircular(直徑20feet). A sigle lane is 12 feet and the distance to the sides of the tunnel is the same. If all the vehicles passing the tunnel should leave at least 1/2 feet distance to the top of the tunnel. What is the max height of the vehicle allowed.

Ans. 15/2

我的理解是，把圖想成半個內接正方形(邊長是12)的圓形(直徑是20)。
而正方形裡的每個點到頂點都要預留1/2。所以用正方形邊長的一半6-1/2=11/2
我求不出15/2的答案。請問我想錯了哪一步呢?

謝謝!!

[homaru]

這題同下~
http://www.formosamba.com/phpBB3/viewtopic.php?t=1732

[clelia]

感激不盡∼∼