Simple division. 269/48=5.60416666667. You probably cannot put decimals, so round to 6.
Step-by-step explanation:
Let ABCD be a rhombus. So, AC (AC = 14 cm) and BD (BD=48 cm) will be its diagonals. Let us assume that diagonals are intersecting at point O.
Since, diagonals of a rhombus are perpendicular bisector.

Hence, length of a side (or all) is 25 cm.