The answer to this depends on the angle at which they intersect. If it intersects<span> the cylinder perpendicular to the axis then a circle is formed. </span><span>If the plane intersects the cylinder at an angle, it will form an ellipse. This will be true until the plan is parallel with the axis of the cylinder. At that point, the surface will become a rectangle.</span>
The perimeter of a rectangle is =2 (w+L)
