ANSWER—C.................................
Answer:
The formula A=12bh is used to find the area of the top and bases triangular faces, A= area, b= base, and h= height. The formula A=lw is used to find the area of the three retangular side faces, A= area, l= lenght, and w= width
Step-by-step explanation:
Answer:
The portion of the volume of the cup that is filled with water is 
Step-by-step explanation:
step 1
Find the volume of the paper water cup
The volume of the cone is equal to

we have


substitute


step 2
If the cup is filled with water to half its height, find out what portion of the volume of the cup is filled with water
Remember that
If two figures are similar, then the ratio of its volumes is equal to the scale factor elevated to the cube
In this problem the similar cone has half the height of the complete cone
so
The scale factor is equal to 1/2
therefore
The volume of the cup that is filled with water is equal to the volume of the complete cup by the scale factor elevated to the cube

therefore
The portion of the volume of the cup that is filled with water is

Distribute:
(12n-12)5
60n-60 = A(n)
You can't really find what n is I don't think, because you have 2 unknown variables n and A(n).