A square.
a rectangle.
circle just did it on apex
an oval hemispere * * * * * The cross section must be 2-dimensional so it cannot be a hemispere - or hemisphere, even. I suggest the shape is lenticular: the shape of a convex lens (with equal radii of curvature).
No, a prism has flat sides. Triangular prisms are very common, but any polygon can be the cross section of a prism.
A cross section of a cylinder along its length is called a rectangle. When a cylinder is cut along its length, the resulting shape is a rectangle with a length equal to the circumference of the cylinder and a height equal to the height of the cylinder. The area of this rectangle represents the lateral surface area of the cylinder.
A square.
The shape of a transverse cross section of a cylinder is a circle.
The cross section of cylinder along its length (parallel to the axis of symmetry has the shape of a rectangle.
You cannot have a 2d cylinder. The 2d cross section will depend on the plane of the cross section.
a circle
a rectangle.
If the cylinder is standing on its flat face, the horizontal cross section is a circle. Otherwise, it is a line or a rectangle.
An ellipse or a rectangle, depending on how you cut it.
Holding the knife at different angles, you could cut a cylinder and get a circle, an ellipse, or a rectangle.
It will be a rectangle
The shape of the cross section depends on the 3D object being sliced. For example, if you slice through a cylinder horizontally, the cross section would be a circle. If you cut through a cube diagonally, the cross section could be a triangle or a rectangle, depending on the angle of the cut. Thus, the specific 2D shape observed in the cross section varies based on the object's geometry and the orientation of the cut.
A cylinder is a three dimensional shape with a uniform circular cross section and a finite length.