A cylindrical container with a radius of 68cm and height of 78cm is open at the
top. What is its exact surface area in square centimetres?
If the cylinder were open at the top and bottom ends, like the cardboard tube
that's left after you use up all the toilet paper, the outside surface area
would be given by
square centimeters.
But since it has a bottom, the bottom surface area is a circle, the area of
which is
square centimeters.
The sum of the outside surface area and the bottom circle is a total of
square centimeters.
If it had a top you would add that again, but it doesn't, so the answer is
square centimeters.
[Since you are asked for the 'exact' surface area, don't use 3.14 or 3.1416
for pi, for no decimal is 'exactly' equal to pi.]
Edwin
