CAT 2016 Quantitative Ability

From a rectangular sheet of dimensions 30 cm × 20 cm, four squares of equal size are cut from the four corners. Then the resulting four sides are bent upwards to give it the shape of an open box. If the volume of the box is $1056\mathit{c}{\mathit{m}}^3$ , what is the length of the side of the squares cut from the corners?