To learn frustum of cone
Frustum of cone is the part of cone when it is cut by a plane into two parts. The upper part of cone remains same in shape but the bottom part makes a frustum. To get this part of the right circular cone we have to slice it horizontally or parallel to the base.
The collection of all the points in a plane, which are at a fixed distance from a fixed point in the plane is called a circle.
A circular sector is the portion of a disk enclosed by two radii and an arc.