When the stone is 4 cm above the water surface vertically, the water surface in the cylinder rises 10 cm.

→ Underwater V-stone

=

S stone *(H stone -4)

=S slot * 10

①

When the stone is 8 cm above the water level vertically, the water level in the tank drops 1 cm.

→ 1 cm The volume of water falling is equal to the volume of 4 cm stone rising (8-4=4).

∴S tank =4S stone

②

② Substitute into ① to get:

H stone =44 cm

∴V stone =π*7*7*44=2 156π cubic centimeter