Short-Question

# Is a cone made from a disc?

## Is a cone made from a disc?

A cone is a solid made from a disc, a point not in the same plane as the disc, and all the points between them. Think of an ice cream cone or a traffic pylon and you’ve got the image of a cone. Formally, a cylinder is made of two parallel and congruent discs not in the same plane, and all of the points between them.

Is Triangle a polygon?

A polygon is any shape made up of straight lines that can be drawn on a flat surface, like a piece of paper. Such shapes include squares, rectangles, triangles and pentagons but not circles or any other shape that includes a curve.

### Is a cone polyhedron?

Polyhedrons are space figures with flat surfaces, called faces, which are made of polygons. Prisms and pyramids are examples of polyhedrons. Cylinders, cones, and spheres are not polyhedrons, because they have curved, not flat, surfaces. A cone has one circular base and a vertex that is not on the base.

Is a half space a cone?

Half-spaces (open or closed) are affine convex cones.

## Is a pyramid a cone?

A right circular cone is a circular cone whose altitude intersects the plane of the circle at the circle’s center. Figure %: A right circular cone It is easy to see the close relationship between pyramids and cones. The only difference is the base–a pyramid is a cone with a polygonal base.

What is the construction of a regular polygon?

Construction of regular polygons. A constructible regular polygon is one that can be constructed with compass and (unmarked) straightedge. For example the construction on the right below consists of two circles of equal radii.

### Why are polygons with many sides tedious to construct?

Even with the introduction of equipartition of plane angles [3], most of the angles of the polygons with many sides are tedious to construct because the base angles get larger and close as the number of sides increase. Currently there are many procedures for constructing regular polygons. Each method usually is for a family.

Is there a way to build polygons on the same base?

The answer is yes because there is a method describing the construction of regular polygons on same base which is termed the “two triangle rule”. This assumes that regular polygons drawn on a common base with their centres lying on the perpendicular bisector of the common base have their centres equally separated.

## Which is the only regular lattice polygon to be constructed?

Y Y Y Y N Y N Y N Y N N Y Y Y The ultimate level of constructability would be a lattice polygon where the vertices lie on an integer lattice as shown on the left below. However the only regular lattice polygon is the square – although the octagon shown here is equiangular.