Surface area of a cylinders and prisms A cylinder has a diameter of 9cm and a height of 25cm. What is the surface area of the cylinder if it has a top and a base?

The top and the bottom each have area $\pi(9/2)^2$.  
For the rest, use a can opener to remove the top and bottom of the can. Then use metal shears to cut straight down, and flatten out the metal. We get a rectangle of height $25$, and width the circumference of the top. So the width is $9\pi$, and therefore the area of the rectangle is $(9\pi)(25)$.  
