Volume= 37. 7
V=π r² h/3 = π · 22 · 9/3 ≈37.69911
I hope this helps!
Answer:
Part A) see the explanation
Part B) 
Step-by-step explanation:
Part A)
we know that
A relationship between two variables, x, and C, represent a proportional variation if it can be expressed in the form
or 
Let
C ---> is the total cost (represent the output or dependent variable)
x ----> is the number of books (represent the input or independent variable)
In this problem
we have a proportional relationship between the variables x and C
Part B) we know that
The linear equation is given by

The constant of proportionality k is the same that the slope or unit rate of the linear equation
In this problem the constant k is given

so

For x=12 books
substitute in the equation and solve for C

In function notation

Answer:

Step-by-step explanation:
1) the rule of transformation [degr → rad] is:
![\alpha [rad]=\alpha [degr] *\frac{\pi }{180};](https://tex.z-dn.net/?f=%5Calpha%20%5Brad%5D%3D%5Calpha%20%5Bdegr%5D%20%2A%5Cfrac%7B%5Cpi%20%7D%7B180%7D%3B)
2) according to the formula above:
230°=230*π/180=23π/18 [rad].
-2x^2 + 500x - 350
You need to plug in the equations for C(x) and R(x) into the equation P(x)= R(x) - C(x) and solve.