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  • A shooting star crashes on Earth, and a hideous blob emerges.

    一顆流星撞上了地球, 出現了一隻可怕的黏液怪物。

  • It creeps and leaps, it glides and slides.

    它會爬行、會跳躍、 會滑動、會滑行。

  • It’s also unstoppable: weapons, fire, extreme temperaturesno matter what you throw at it, it just regrows and continues its rampage.

    而且它還所向無敵: 武器、火、極端溫度... 不論你用什麼方式攻擊它, 它總會再生並繼續製造暴亂。

  • Its expansion is breathtaking; it doubles in size every hour.


  • But there’s one opportunity: after each hour, it goes to sleep, forming itself into a flat triangle and resting for a few minutes before it begins eating and growing again.

    但我們有一個機會:每隔一小時它會進入睡眠, 將自己的形狀變成扁平三角形後休息個幾分鐘,接著又會再開始吞噬一切並繼續成長。

  • Your only chance to save the planet involves a satellite-mounted nano-fission ray that can cut through the blob.


  • When the blog is active it heals itself within seconds.


  • However, when you break the sleeping blob into two triangles, you make a critical discovery.


  • The acute triangle portion, with all angles less than 90 degrees, is inert.

    被切成銳角三角形的部分,也就是所有的角都小於 90 度的三角形,已不再具有生命力。

  • It neverwakes up.”


  • The obtuse triangle, which has an angle greater than 90 degrees, wakes up as usual and keeps growing.

    至於鈍角三角形,也就是有一個角大於 90 度的三角形,還是一樣會醒來並繼續成長。

  • Similar experiments show that all shapes other than acute triangles, including right triangles, will also wake up.

    類似的實驗結果顯示, 除了銳角三角形之外的所有形狀,包括直角三角形,都還是會醒來。

  • For the next few minutes, the blob is sleeping in its obtuse triangle form.


  • You can make clean, straight-line cuts between any two points on or inside the triangle.


  • But youll only have time to make 7 cuts while the satellite is above you.


  • By the time it completes its orbit and returns, the blob will have consumed the entire world, if even a single portion that will wake up remains.


  • How can you cut the blob entirely into acute triangles and stop it from destroying the planet?


  • Pause the video now to figure out for yourself


  • Answer in 3, 2 ,1.


  • While this seems doable at first, there’s a hidden difficulty when it comes to avoiding obtuse and right angles.

    雖然一開始這個方法看似可行, 但若想避免鈍角和直角,便會碰到一個隱藏的困難點。

  • Every time you make a cut that reaches an edge, it either makes an acute and an obtuse angle, or two right angles.


  • That makes it seems like youre doomed to keep creating obtuse angles.

    看起來似乎你注定會 一直製造出鈍角。

  • But as with so many of life’s problems, we can look to pizza for inspiration.


  • Imagine squaring off the outside of a pizza, so that instead of a circle, it’s an octagon.

    想像一下,把披薩的外緣切平, 讓它變成八角形,而不是一個圓。

  • When we cut it into slices, each of the eight triangles is acute.


  • This works with larger polygons too.

    對於邊數更多的多邊形, 這招也一樣可行。

  • Importantly, it also works for some polygons with fewer sides, including heptagons, hexagons, and pentagons.


  • That’s good news, because if you cut off the sharp corners of the blob triangle, a pentagon is exactly what youll be left with.


  • And just like a pizza, you can cut the blob pentagon into 5 acute triangles.

    而就像比薩一樣, 你可以把怪物五角形切成五個銳角三角形。

  • That’s 7 cuts, and it renders the blob completely inert.


  • Youve saved the day!


  • Now you just need to figure out what to do with all of these giant, practically indestructible triangles.


  • Here is a bonus riddle for you: are triangles the best shape?


  • Just kidding, that's not a riddlebut it is worth discussing! Watch these lessons and decide for yourself.


A shooting star crashes on Earth, and a hideous blob emerges.

一顆流星撞上了地球, 出現了一隻可怕的黏液怪物。

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C1 高級 中文 TED-Ed 三角形 怪物 比薩 公佈 衛星

你能解開不可阻擋的怪物之謎嗎? (Can you solve the unstoppable blob riddle? - Dan Finkel)

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    林宜悉 發佈於 2021 年 10 月 02 日