(b) 13 cm

Let ABCD be the rhombus with diagonals AC and BD intersecting each other at O.
We have:
AC = 24 cm and BD = 10 cm
We know that diagonals of a rhombus bisect each other at right angles.
Therefore applying Pythagoras theorem in right-angled triangle AOB, we get:
AB2 = AO2 + BO2 = 122 + 52
= 144 + 25 = 169
AB = \(\sqrt{169}\) = 13
Hence, the length of each side of the rhombus is 13 cm.