Help me ASAP find the area of the shaded region type answer in terms of pi

The vet charges $45 for an office visit and $10 for each vaccination your dog needs. write an eaquation

Apatient is to be given 35 milligrams of demerol every 4 hours. you have demerol 50 milligrams/milliliter in stock. how many milliliters should be given per dose?

Which equation can be used to measure the density of water in a spherical water tank? let w represent the number of water particles within the region.