9 dots problem | Join with 4 lines (Experts) | Join with 3 lines (Masters)

This is a classic interview question, to test the creative thinking of a candidate.
Challenge for Experts:
Your task is to join the 9 dots with 4 straight lines, without lifting the pen.

Challenge for Masters:
The task is to
Join the 9 dots with 3 straight lines without lifting th pen.

So this problem doesn't need hard work or calculation.... it just needs the smart way of thinking outside the box...
And many big organizations present this challenge to the candidates in interviews, to identify the most intelligent candidate amongst them.

The video has complete explanation of the logic behind the solution.
Please comment below your answers and suggestions. Also LIKE the video and SUBSCRIBE to my channel if you are new.

Also, please give a try to difficult puzzles and Interview Questions Answers specific to Puzzles and Riddles.

[joshkazdan]

The three-lines solution seems a little bit bogus to me. If the points are infinitesimal (as they should be), then a three line solution is not possible. Taking the three-line solution to its logical extreme, if we just make the points thick enough we can touch them all with a single line (or even find a single point in their intersection).

[EthyEth]

a lot more people would successfully come to these same conclusions if the rules of where lines could be drawn were stated very clearly at the beginning.

Due to traditional thinking and strict rules in pretty much all facets of adult life and especially in our school career (shapes the way we think very precisely).
We limit our thinking in these problems to staying in the lines (dots) aka straight lines through middle sections of dots only.

If you simply say, there are no rules to where you draw your straight lines, atleast 50% of people who would normally not find the solutions would then easily find atleast the first less difficult version.

[voltairediaz]

I can join all the dots with one line without lifting the pen. Think outside the box. Think logically.

Using a pen brush that's thick enough to cover all the dots in one stroke.

[simonmxc]

hold the pen pointing up, then move the paper over the pen. You can lift the paper.

[darklawtivity]

I can connect with one line if I make it thick enough. The point is to connect tiny dots with four tiny lines. Those are circles and if that is the problem then yes connect with three lines is the goal.

[subhajitsarkar]

Sir...by definition point is what has no dimension...so there is no difference between its center and tangent...so such line can't be drawn🙂

[PKaushikYATHIRAJ]

A dot is assumed to have no dimensions. And a line is assumed to have only one dimension. So the master level is not possible. Thank you

[michellepr]

Thank you now I know my homework answeres

[SonicVisualGR]

title says "dots", not "circles", so "Join with 3 lines" is problematic ;)

[ivanajohanna]

How would you calculate the shortest route through all the 9 circles, provided that each straight line goes through the centre of one circle?

[braceyourselvesfortruth]

Couldn't hack expert, but with the context of expert I solved master rather quickly.

[kabir]

awesome logic... explained very well👍👍

[protorhinocerator]

You can do it with one line. Super expert mode.
It requires folding the paper thin and then wrapping it into a coil. The dots line up and you can cross them all with one stroke.
When you unfold the paper, the lines will no longer be solid (they will be dashed) but the center of each dot will be marked.

[mikaruyami]

If you want to make this puzzle more interesting.

You have a square piece of paper with 9 evenly placed dots representing central points on the paper.
Connect all the central points using no more than 4 straight lines on the paper.
The lines must be all be connected together and you cannot have more than 2 end points.
The lines cannot leave the paper.
There is a solution for this that is using 1, 2 or 3 lines.

[AbdulKarim-cwcv]

Is there any formula to solving such problems?

[dollcyjain]

Amazing puzzle. But i thought joining 9 dots with 4 straight line is more difficult than joining with 3 straight line

[Wyldone]

Now join all nine dots with one line.


It's possible with the docs on a cylinder. EG like a screw -non euclidean space

[dhiraj.govindvira]

If dot are too small then it's not work.
But in this it will work fine.

[smottiebug]

the 3 lines would only work if your dots were large enough to connect then at a diagonal line.
on a single piece of paper .

if the dots were the about the same thickness of the pen line or even a bit bigger. It could technically be done at the slightest angle. Although it would require a mile of paper to do it.

So the actual question you should ask is;
How to connect 9 "*Circles*"with only 3 lines?

That is, f you wanted it to be solved on just one piece of paper. lol

[Stankpopbetterlife]

bro tysm i tried doing in class we actually did it!