Cylinder

Cylinder Facts
Notice these interesting things:
	It has a flat base and a flat top
	The base is the same as the top, and also in-between
	It has one curved side
	Because it has a curved surface it is not a polyhedron.

And for reference:
	Surface Area = 2 × π × r × (r+h)
	Surface Area of One End = π × r² Surface Area of Side = 2 × π × r × h
	Volume = π × r²× h

An object shaped like a cylinder is said to be cylindrical

Volume of a Cylinder

Just multiply the area of the circle by the height of the cylinder:

Area of the circle: π × r²
Height: h
Volume = Area × Height = π × r²× h

There is an easy way to remember:

Imagine you just cooked a pizza.

The radius is "z", and the thickness "a" is the same everywhere ... what is the volume?

Answer: pi × z × z × a

(we would normally write "pi" as π, and z × z as z², but you get the idea!)

It Doesn't Have to Be Circular

Usually when we say Cylinder we mean a Circular Cylinder, but you can also have Elliptical Cylinders, like this one:

You can even have stranger cylinders: if the cross-section is curved and is the same from one end to the other, then it will still be a cylinder.