Definition: A surface created by projecting a closed two-dimensional curve along an axis intersecting the plane of the curve.

Alright class, settle down and let’s take a look! That definition you read – quite a mouthful, isn’t it? Let’s break it down in a way that makes more sense. It's about understanding shapes, and specifically, cylinders . Think of it this way: A cylinder is basically a three-dimensional version of something you might draw on paper. It’s like a tube – think of a can of soup, or a roll of toilet paper. Let’s unpack that dictionary definition piece by piece: “A surface created…” - This means we're talking about the outside shape of the cylinder. “…by projecting a closed two-dimensional curve…” – Now this is where it gets a little trickier, but think of drawing a circle on a flat sheet of paper. Imagine you’re shining a light down onto that circle and “projecting” its outline onto a wall. That circle becomes a line! A cylinder is formed in a similar way - taking a 2D shape (like a circle) and turning it into a 3D surface. “…along an axis intersecting the plane of the curve.” – This just means that the "light" (or the axis, which is like a line running straight through the center) goes right through the middle of your 2D shape (the circle). Simply put: A cylinder is a solid shape with two circular bases connected by a curved surface. It's all about rolling something up! (Rhyme time!) "A cylinder’s a roll, it’s true, With circles at both, shiny and new!" Do you have any questions? Let’s see if we can draw one to really understand what we've discussed.