Two vertical posts are in level ground at 150 feet apart. A bendable cable, but one that does not stretch from its original length, is 150 feet and 1 inch in length. The cable is fastened in between the two vertical posts at ground level on each side.

The middle point of the cable is lifted up until it is taut, and the ground and the middle sections of the cable form an obtuse isosceles triangular shape.

Is there room enough for you to crawl through in the space between the ground and underneath the middle of the cable?

* The length of the cable has been edited. *


closed as off-topic by StephenTG, Aggie Kidd, Ivo Beckers, Khale_Kitha, DylanSp Mar 17 '16 at 19:32

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "This question is off-topic as it appears to be a mathematics problem, as opposed to a mathematical puzzle. For more info, see "Are math-textbook-style problems on topic?" on meta." – StephenTG, Aggie Kidd, Ivo Beckers, DylanSp
If this question can be reworded to fit the rules in the help center, please edit the question.

  • 1
    $\begingroup$ Why isn't there spoiler formatting in comments? $\endgroup$ – Fᴀʀʜᴀɴ Aɴᴀᴍ Mar 17 '16 at 18:23
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    $\begingroup$ I'm voting to close this question as off-topic because it appears to be a math problem and is dependent upon the size of the person reading it as to the validity. $\endgroup$ – Khale_Kitha Mar 17 '16 at 19:21
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    $\begingroup$ Math puzzles are math problems anyway. It's a math puzzle. It's a variation of a math puzzle that I read in a puzzle book. There is no need to put it on hold or to vote to close this question. I am an expert on many puzzles, and I am surprised that someone would deem this not a puzzle. $\endgroup$ – Olive Stemforn Mar 17 '16 at 22:37
  • $\begingroup$ It doesn't say where along the posts the cable is fastened. If the posts are 20 feet high and the cable is fastened to the top, then the answer is obvious. Source: you can walk under power lines. $\endgroup$ – Ian MacDonald Mar 18 '16 at 0:14
  • $\begingroup$ I edited the problem for the cables being attached at ground level. $\endgroup$ – Olive Stemforn Mar 18 '16 at 2:08

I think

Probably? I mean, assuming you can pretty much just lie on the ground and scoot?


The isosceles triangle is also two right triangles with bases of $900$ inches and hypotenuses of $900.25$ inches, making the altitude about $21$ inches (actually $21.214676523$ish)


still yeah. I mean it's even longer. of course.

  • $\begingroup$ That's a commando crawl, which, I guess, is still technically a crawl. $\endgroup$ – Matt Mar 17 '16 at 18:34

Yes. Because each side of the cable can be considered an isosceles triangle with a right angle. We know the ground is 75 feet or 900 inches on each side, and the taut cable above it would be 900.25 inches.
900² = 810,000
900.25² = 810,450.0625
The positive square root of 450.0625 is about 21.2146765...
That should be enough room for most fit people, though it might be tight.


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