The height of the cylinder is 8 inches.

We'll be analyzing the surface area of a round cylinder - in other words, the amount of material needed to "make a can

A cylinder (round can) has a circular base and a circular top with vertical sides in between. Let rrbe the radius of the top of the can and lethhbe the height.The surface area of the cylinder, AA, isA=2r2+2rhA=2r2+2rh(two circles, onefor the top and one for the bottom plus a rolled up rectangle for the sides).

Part a: Assume that the height of your cylinder is 88inches.ConsiderAAas a function ofrr, so we can write that asA(r)=2r2+16rAr=2r2+16r. What is the domain ofA(r)Ar? In other words, for which values ofrrisA(r)Ardefined?

r(A) =

Part c: If the surface area is 125125 square inches, then what is the radiusrr? In other words, evaluate r(125)r125.Round your answer to 2 decimal places.

Hint: To compute a numeric square root such as 17.317.3, you could

• Use a spreadsheet such as Microsoft Excel or OpenOffice Calc and type in =sqrt(17.3)
• Use a browser to connect to the Internet and type in sqrt(17.3) into a search field
• Use a calculator

The radius is what number inches if the surface area is 125 square inches?

r = radius Areas = 1 1- h = height Area = h(2xr) Circumference