Let, coordinate of point A = (x, y).

$$\therefore\,\,\,$$ For point A,

$${x \over {\cos {{30}^ \circ }}}$$ = $${y \over {\sin {{30}^ \circ }}}$$ = 2

$$ \Rightarrow $$ x = $$\sqrt 3 $$

and y = 1

Similarly, For point B,

$${x \over {\cos {{75}^ \circ }}}$$ = $${y \over {\sin {{75}^ \circ }}}$$ = 2$$\sqrt 2 $$

$$\therefore\,\,\,$$ x = $$\sqrt 3 - 1$$

y = $$\sqrt 3 + 1$$

For point C,

$${x \over {cos{{120}^ \circ }}}$$ = $${y \over {sin{{120}^ \circ }}}$$ = 2

$$ \Rightarrow $$$$\,\,\,$$ x = $$-$$1

y = $$\sqrt 3 $$

$$\therefore\,\,\,$$ Sum of the x - coordinate of the vertices

= 0 + $$\sqrt 3 $$ + $$\sqrt 3 $$ $$-$$ 1 + ($$-$$ 1) = 2$$\sqrt 3 $$ $$-$$ 2