s=15
Whatever the number of sides of a polygon,
the sum of its exterior angles is always 360∘
Further, each pair of exterior angle and interior angle adds up to 180∘
Hence in a polygon with s sides (or angles),
the sum of all the interior and exterior angles would be 180∘×s
and sum of interior angles would be 180∘×n−360∘=180∘(s−2)
As sum of angles is 2340∘
Hence, 180(s−2)=2340 or s−2=2340180=13
and s=13+2=15 and polygon is a Pentadecagon.
i hope u understand :)