Help with a calculus question?

Question

I understand this isn't high level calculus if it is even calculus. But the question is "Write a formula for the function and use the formula to find the indicated value of the function. The volume V of a sphere as a function of the sphere's radius r; the volume of radius is 3 cm" I really don't even understand what I am supposed to do.

Answer 1

For a sphere, V = 4/3 π r³

So if r=3, then r³ is 27 so just do it out on your calculator

Answer 2

Volume of a sphere = (4/3)(pi)(r^3)

V(r) = (4/3)(pi)(r^3)

V(3) = (4/3)(pi)(3^3)

V(3) = (4/3)(pi)(27)

V(3) = 4(pi)(9)

V(3) = 36pi cm^3

113 cm^3 is correct because 36(3.14) = 113.04... etc.