# Cylinder

In the picture below, we have two parallel and distinct planes,, a circle R contained in and a straight r that intercepts , but not R:

For each point Ç Of region R, let's consider the segment , parallel to the straight line r :

Thus we have:

We call it cylinder, or circular cylinder, the set of all segments congruent and parallel to r.

## Cylinder Elements

Given the following cylinder, consider the following elements:

• bases: the center circles O and O'and lightning r

• height: the distance H between the plans

• generatrix: any end segment at the points of the base circumferences (for example, ) and parallel to the straight r

## Cylinder Classification

A cylinder can be:

• oblique circular: when the generatrices are oblique to the bases;

• straight circular: when the geratrices are perpendicular to the bases.

Look:

The straight circular cylinder is also called the revolution cylinder because it is generated by the complete rotation of a rectangle on one side. Thus, the rotation of the ABCD rectangle by the side generates the following cylinder:

The straight contains the centers of the bases and is the axis of the cylinder.

Next: Cylinder Sections