6
$\begingroup$

Your task is to create independent triangles (which means they do not have the same edge) by drawing straight lines as exemplified below:

enter image description here

In this example, there are $5$ lines and $5$ independent triangles and no triangle exists with the same edge with another triangle.

so,

At least how many straight lines do you need to have $11$ independent triangles without having any triangle having the same edge as given above?

Improve this question
$\endgroup$
5
  • $\begingroup$ Is Independent triangles means there is at least one edge that is not touched by another triangle? $\endgroup$
    – rudra
    Dec 2, 2017 at 14:04
  • $\begingroup$ @rudra no edge is supposed to be common between two triangles at all in the graph. $\endgroup$
    – Oray
    Dec 2, 2017 at 14:06
  • $\begingroup$ It seems 12 independent lines are required though they can form 12 such triangles instead of required 11 :-( $\endgroup$
    – Mea Culpa Nay
    Dec 2, 2017 at 14:30
  • $\begingroup$ Doing some search Oray, isnt KOBON triangle same as what you are asking? $\endgroup$
    – DrD
    Dec 2, 2017 at 14:58
  • $\begingroup$ @DEEM yes :) but asking this as a question is a puzzle itself. $\endgroup$
    – Oray
    Dec 2, 2017 at 14:59

2 Answers 2

Reset to default
5
$\begingroup$

I created 11 independent triangles with ...

... 7 lines:

solution

Improve this answer
$\endgroup$
3
$\begingroup$

with 7 lines enter image description here could be same as the previous answer

Improve this answer
$\endgroup$
1
  • $\begingroup$ I got this before seeing previous answer. However I also found that something like this is defined as KOBON triangles? I may be wrong $\endgroup$
    – DrD
    Dec 2, 2017 at 15:00

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.