CD floating in milk

An opaque disc of diameter $66\text{ mm}$ is floating on a liquid of refractive index $\sqrt 5$ . The liquid is filled in a wide vessel to a depth of $3.3\text{ cm}$ . A point source of light is held in the air above the center of the disc at height $3.3\text{ cm}$ above it.

Determine the diameter (in $\text{mm}$ ) of the shadow formed on the bottom of the vessel.