see the attached picture with letters to better understand the problem
we know that
the figure is a regular hexagon
A regular hexagon has:
Interior Angles of 120°
so
in the triangle ABC
BC=2 units
∠ABC=30°
∠BAC=60°
tan 30°=AC/BC
solve for AC
AC=BC*tan 30°-------> AC=2*(√3)/3
Apothem is equal to AC
Apothem=(2/3)√3
the answer is(2/3)√3
