Suppose the water rises by h cm.
Clearly water in the cylinder forms a cylinder of height h cm and radius 10 cm.
∴ Volume of the water displaced = Volume of the cube of edge 8 cm
⇒ πr^{2}h = 8^{3}
⇒ 3.142 × 10^{2} × h = 8 × 8 × 8
⇒ 8 × 8 × 8/3.142 × 10 × 10 cm = h
h = 1.6 cm