Find the volume and surface area of a cylinder, of length 20cm and radius 5cm.

A diagram is often helpful to draw for questions like this. 1.) Volume. For the volume of a cylinder, you must first find the area of the face, and multiply by the length. The formula for this is Vol= πr^2 . l In this case r= 5 and l= 20, so the volume will be π . 5^2. 20 = 500π cm^2. 2.) Surface area is a little more tricky as you must decompose the cylinder down into its composite shapes. From the diagram, you can see these shapes are two circles at either end, and if it was rolled out flat actually a rectangle, of length 20 and width equal to the circumference of the circles. The surface area then will be equal to 2(πr^2)+ 2πr . l In this case this comes to 250π cm.