The definition of density is mass divided by volume ( mass/volume)
The picture shows that the mass of the object is 482.63 grams.
The picture is using what is known as water displacement in order to find the volume of the irregularly shaped object. Water displacement takes the difference in the height (volumes) of the graduated cylinder with versus without the object placed inside. Therefore:
Volume with the object in the graduated cylinder - volume without the object = volume of the object
Thus, the volume of the object is 800mL - 600mL = 200 mL
Now that the mass and volume have been identified, the density can be determined:
482.63 g/ 200 mL = 2.41 g/mL
Please note that the unit must reflect the formula (g/mL).