The brain teaser is worded as:
Isolate the circles within the triangle so that they don't share any area with each other using only 2 lines.
The lines may not cross but can touch only once.
Now I can see that this is real easy if you are allowed to use curved lines.
(as in the 2nd image)
However, what if you MUST use straight ones?
We thikn that the question is just badly worded but should be straight lines only. Otherwise it ws too easy & the question is usually hard.