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Random Point Within a Regular Pentagon (Posted on 2024-06-22) Difficulty: 3 of 5
You choose a random point within a regular pentagon having unit sides.

What is the average distance to the five sides?

See The Solution Submitted by K Sengupta    
Rating: 5.0000 (1 votes)

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Some Thoughts Solution by Geogebra | Comment 1 of 2
It looks like the answer is sqrt((5+sqrt(20))/20) or about 0.6881909602

Approximation from this drawing 
https://www.geogebra.org/geometry/tqwh2wnx

You can see the sum of the five distances appears to be invariant.

Then look that up on the inverse symbolic calculator
https://wayback.cecm.sfu.ca/cgi-bin/isc/lookup?number=0.6881909602&lookup_type=simple

The answer is almost certainly correct given the square roots of 5.
The proof would be more involved, but not too bad.



  Posted by Jer on 2024-06-23 14:55:56
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