The diagram shows a hexagon. Three interiors angles are as shown. The remaining three interior angles are equal. Find x. Ans x = ___ °

1. Find the sum of the interior angles of the hexagon.

For a hexagon, $n=6$.

Sum of interior angles
$=(n-2)\times 180^\circ$
$=(6-2)\times 180^\circ=720^\circ$

2. Find the total of the three given interior angles.

The three given angles are $120^\circ$, $90^\circ$ and $135^\circ$.

$120^\circ+90^\circ+135^\circ=345^\circ$

3. Use the three equal remaining angles to find $x$.

The remaining three angles are equal, so
$3x=720^\circ-345^\circ$
$3x=375^\circ$
$x=125^\circ$