Please help me its very urgent!​

Find the constant of variation for the relation and use it to write an equation for the statement. then solve the equation.

The radius of a sphere is 3 inches. which represents the volume of the sphere?

20.ju inces. which ordered pair is a viable solution if x represents the number of books he orders and y represents the total weight of the books, in ounces? (-3,-18) (-0.5, -3) (0,0) (0.5, 3)