Help with surface area for right cylinder.....?

Question

so if you are trying to find the surface area of a right cylinder given the circumference(18pi) and height(10ft) how would you set it up?

Answer 1

Area = circumference times height

Area = 10* 18 * 3.14159 = 565.4862 sq ft

Answer 2

When you say the circumference is "18pi," are you implying the diameter of the cylinder is 18 ft? Also, you didn't mention if the cylinder is open or closed. If open, are you interested in the outside surface only, or the sum of the inside and outside surfaces. If closed, you must include the outside surface areas of both ends.

I'll give you the formulas to compute the various surfaces, but since your question is so vague, you'll have to figure out which to use and which to ignore.

For one surface of one end-cap: a = pi*r^2 (r is probably 9 ft).

For one surface of the cylinder: a = 2*pi*r*h (r is probably 9 ft, h is 10 ft, and pi = 3.14159).

Calculate the two areas, then figure out what the question really means. Is there a picture? Add up the areas of the surfaces you decide to include..................

Answer 3

you can think of a cylinder as a stack of circles (if you are not including the ends)

so, multiply the circumference*height

18pi in*10 in=180*pi in^2

if you need to include the surface of the round ends of the cylinder then you need the area of a circle (pi*r^2)

to get r you have to remember that pi*diameter=circumference

so if the circumference is 18pi, the diameter is 18
so the radius is 9
so each round end surface has area pi*9^2

and there you have it
keep at it