nope three of then fit into 15m ????agree?
Why do you think it's 5m Hinekadon? Where's your working?
What if I told you it was 3.75m? Would that help?
Yes I am an agent of Satan, but my duties are largely ceremonial.
nope three of then fit into 15m ????agree?
Is this considered cheating...
hinekadon (10-08-18)
have you been putting cables thru ducts ????
Nope... you're not offering any proof of your answer.
Everybody knows Red cars go faster than Blue cars.
For example.... I can demonstrate the two smaller circules are 7.5 because there are two of them across the 15m diametre.
My working is 15/2=7.5.
Show me the mathematical reason why you think that smaller circle is 5m diameter and not 3.75m.
Yes I am an agent of Satan, but my duties are largely ceremonial.
hinekadon (10-08-18)
If it's wrong then the good people at Solidworks have got some big problems!
Perhaps this looks more symmetrical to you, three equal-sized 5m circles fit within the outer 15m circle...
...I couldn't be bothered doing the actual math, that's what CAD is for! (No point having a dog and barking at the postman yourself!)
EDIT: If you want math, 15 / 3 = 5
Last edited by Bigfella237; 10-08-18 at 08:46 PM.
yep except i measured the screen with my vernier calipers and divided it out the maths are right unless im over seventy and in that case im allowed to be wrong as noone cares about me any way hehehe
But that says nothing Bigfella. You don't know that smaller circle is 5m.
If like I said, they are 3.75m, then your drawing is a lie. It's the loch ness monster of maths... look... I see three humps, it must be a monster.
Like the hanging cable, you need to provide a mathematical proof of your answer. You've cut and past an answer without any proof.
And your picture gives an even greater precision on smaller circles, but you have absolutely no idea how they got those numbers, let alone 5m for the circle in question.
I'm telling you that circle is 3.75m. Prove me wrong and show me how I'm wrong.
Imagine you're sitting in a class without a calculator or the internet to do you thinking for you.
How do you explain how 3.75+3.75+3.75=15 ?
It doesn't.... It's a cut and paste an answer. If you did that in a real maths test, you'd get zero. Which is why you need show you're working
Yes I am an agent of Satan, but my duties are largely ceremonial.
ok sitting at a desk with no calculator only pen and paper and your diagram on another sheet of paper ok
get your finger and put it on the diag mark the distance across the circle on your finger , transfer this to the 7.5 circles and the dia is less then see how many times it will fit into the circle this fits the larger dia 3 times therefore will go 15 divided by three =5 which is the question you asked isnt it ?
How can the drawing be a lie?
Regardless of the dimensions, it's obvious that the two equally-sized circles are half the diameter of the outer circle; and the three equally-sized circles are one-third the diameter of the outer circle; and finally that the 'one-third' circles intersect the circumference of the 'one-half' circles and the outer circle, as they do in your original drawing...
Anyway, life's too short and I have better things to do so please don't think me rude if I don't reply to further posts. I do suggest you recheck your own math if you think the answer is something other than 5m though.
Andrew
How can the drawing be a lie?
See this picture... how can the Loch Ness monster be a lie?
You mean 15 / 3 = 3.75"15 / 3 = 5"
Your answer is not more correct than mine than yours for the exact same reason..... I've offered you absolutely no proof of my 3.75m answer.
Cut and paste. You copied your answer from somebody else's work and you have no idea how they got the answer of 5.
And you have no idea how I got the answer 3.75.
Try harder !
It's a maths puzzle, not a jigsaw puzzle.
Yes I am an agent of Satan, but my duties are largely ceremonial.
the dia of the blue has no bearing on the red circle, as the red is assumed to be the size to gauge against, but thats not stated when you ask the question ,we only assume it is relevant to the question as its on the same page , therefore, you as the one asking the question can say whatever size you choose to be the diameter of the blue circle ok no humps then
Correct, the Blue circle should have no bearing on the Red circle. They are related in the ratios that Bigfella posted in the picture, but as I said, this is a maths puzzle. How do you know it is or it isn't with proof?
The simple example is given already. You know the yellow circles are 7.5m because.... You can prove this because exactly two of them fit across the diameter of the Red circle. 15/2=7.5m.
The problem with the Blue circle is that you cannot be sure that maybe 2.8 or 3.14 of them fit across the circle. You only have one to work with as an example.
You cannot pretend there are two other circles that you magically cut to the same size and paste them into the puzzle and offer that up as an answer. 15/3**=5 **You don't know this value is 3. You guessed it, therefore 5m is a guess answer.
That's not science or maths, it's a logical fallacy. (Precluding)
So there is a mathematical proof for the answer.
How about I push you in the right direction.
What's the distance between the center of the Yellow circle and the Blue circle?
Remembering that you do not yet have proof of the size of the Blue circle, so you can't tell me it's 5m. You answer should leave no doubt it is truly 5m.
Just to make you feel really bad, I stole this from a year 8 maths test. So they have to do it without a calculator.
Yes I am an agent of Satan, but my duties are largely ceremonial.
hinekadon (11-08-18)
come on trash im to old for this one, closer to the grave than the center of a circle but do enjoy the exercise of the brain and i do enjoy putting a spanner in the works as well hahaha
has everyone else chickened out ?????
Ok... I shall provide the proof that the blue circle is indeed 5m diameter.
So how do we get this answer.... The first thing to do is to ignore the 15 metres. This causes confusion.
Lets just look at the small circle and consider it's radius. We will of course call this "r".
Next is to look at the yellow circles. Lets give them a simple value and use them as a benchmark. Lets make their radius 1.
So now we know that
- The unknown radius of the blue circle is r
- The radius of the red circle is 2.
- The radius of the yellow circle is 1.
The distance from the center of the yellow circle to the center of the red circle is 1
The distance from the center yellow circle to the center of the blue circle is 1+r
The distance from the center of the red circle to the center of the blue circle is 2-r
These form a right angle triangle so now we can just use Pythagoras to find what r is. a² + b² = c²
(2-r)² + 1² = (1+r)² expand this out to 4-4r+r²+1 = 1+2r+r² rearrange r terms to 4+r²+1 = 6r+r²+1
simplified 4+(r²+1) = 6r+(r²+1) which gives us 4=6r OR r = 2/3
Since the simplified scale was 1 ≈ 7.5 this means the blue circle is 7.5 x (2/3) = 5m
Last edited by trash; 11-08-18 at 12:57 PM.
Yes I am an agent of Satan, but my duties are largely ceremonial.
Here's an easy one. <evil laugh>
There is more than one solution to this puzzle.
So far I know of four solutions to this question. Some are better answers than others for reasons which will become obvious.
Yes I am an agent of Satan, but my duties are largely ceremonial.
My solution would be to fork out the cash for 3 intermediate switches
Interesting nobody even attempted the switch puzzle?
Yes I am an agent of Satan, but my duties are largely ceremonial.
night watchmans circuit
OK... looks like nobody is up to the challenge.
This question was posted by one of our radio club members.
This was the first solution proposed.
This was the second solution posted.
This was the third solution posted.
All of these answers have the problem that they use a short circuit to turn the light off. They would blow a fuse if one was in the circuit.
The original question did not specify a fuse so I did not include it either.
However... I had found two solutions which do not blow the fuse and answer the question as I think was intended.
This was my first answer.
This was my second
Yes I am an agent of Satan, but my duties are largely ceremonial.
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