It is a circle - or at its extreme, a point.
A prism. A prism is named for its base, eg a triangular prism has a triangle for the base. If the base is a circle, the circular prism is called a cylinder.
It is the base of the cone
All cross sections of a square pyramid that are parallel to the base are squares
a. the point farthest from the base: the vertex of a cone or of a pyramid. b. a point in a geometrical solid common to three or more sides. c. the intersection of two sides of a plane figure.
The area of a trapezoid = 1/2 (altitude)(base 1 + base 2) *altitude can also be called the height, or the spacing between the parallel sides. Base 1 is the length of one of the parallel sides, and base 2 is the length of the other parallel side.
Every solid. All you need is the intersection with a plane parallel to the base.
I'm assuming you are looking for the name of the conic section produced by this type of intersection? If a right circular cone is intersected by a plane parallel to one edge of the cone, the resulting curve of intersection would be a parabola. If the intersecting plane was parallel to the base, it would be a circle. If the intersecting plane was at any angle between being parallel to the base and being parallel to an edge, it would produce an ellipse or part of an ellipse (depending on whether the intersection was completely within the cone).
The shape described by the intersection of the cone and the plane is simply a circle.
The interception of a plane with a cone parallel to the base of the cone is a circle.
A circle.
It creates a trapezium frustum.
It is a horizontal cross-section. Its shape will depend on the shape of the solid and its orientation.
If it's parallel to the base, it's a circle. If it doesn't go through the base, it's an ellipse. If it's does, it's hyperbolic/parabolic.
This kind of conic section is a circle
This is called an ellipse.
A prism. A prism is named for its base, eg a triangular prism has a triangle for the base. If the base is a circle, the circular prism is called a cylinder.
When a cone is sliced parallel to the base then the shape produced is a circle. If the cone is sliced at an angle so that the cut goes completely through the cone then an ellipse is produced. If the cut is made perpendicular to the cone's base then the shape produced is a parabola.