Mathematical coincidences
Unexpected approximate relations between trascendental numbers can be intriguing. You can read in Wikipedia about many of them. One can have fun looking for new coincidences. So far I found the following:
π≈
,
with 0.0006% error.
π≈ 
,
with 0.0002% error.
e ≈ 
,
with 0.000 000 03% error.