Surface area question, please HELP?

Question

Write an expression for the surface area of a closed can that has volume of 100 cubic units:

a) 2(pie)(r)^2 + (200/r)
b) 2(pie)(r) + (100/[pie][r]^2)
c) 2(pie)(r)(h) + (pie)(r)^2
d) 100/ (pie)(r)^2

Answer 1

Hard to say... you need to know the radius of the can and its height. C is the formula for surface area of a cylinder, but we don't know r or h.

Answer 2

The only correct choice listed is (c), which is the formula for surface area of a cylinder. Note that answer (c) doesn't even have anything to do with the knowledge of the volume. Since volume is dependent upon both r and h, it's impossible to determine either with the given information.

Answer 3

a is correct . It is a closed can . So surface area =surface area of both ends as well as the cylinder

i.e. 2Pir^2 +2Pirh

but Pir^2h =100 so 2Pirh =200/r

So can be written as 2Pir^2 +200/r

Answer 4

Let radius = r and height = h
V = π r ² h
h = 100 / (π r ²)
S.A. = 2.(πr ²) + 2π r.h
S.A. = 2(π r²) + 2π r.100 / (π r²)
S.A. = 2 π r² + 200 / r
ANSWER a)

Answer 5

its rather confusing!!!