Question

A cone has ____ curved edges:
$\left( a \right)1$
$\left( b \right)3$
$\left( c \right)0$
$\left( d \right)4$

Answer 1

Hint: We are asked to find the number of curved edges of a cone. For this, we first need to be aware of some geometrical properties of the cone. We need to be aware about the number of faces, vertex and other things of the cone.

Complete step by step answer:
A cone is a distinctive three-dimensional geometric figure that has a flat surface and a curved surface, pointed towards the top. The pointed top of the cone is called the apex, whereas the flat surface at the bottom is called the base. A cone is formed by a set of line segments, half-lines, or lines connecting a common point, the apex, to all of the points on a base that is in a plane that does not contain the apex.
A cone with centre $A$ of the base and vertex $B$ looks like this:

Now, we are asked to find the number of curved edges of the cone. For that we need to be aware about the definition of a curved edge. An edge is where 2 faces meet. Now, the cone has two faces. One is curved and one is the circle which is the base. And there is only one circular edge which connects them both. So, the cone has one circular edge.

So, the correct answer is “Option a”.

Note: When we are dealing with 2D shapes, an edge is simply a line connecting the vertices. But when we are in 3D, an edge may not always be linear, like in this case. Since we are asked to find the curved edge, do not get confused between the 2D and 3D edges. You might then mark the answer as 0 because a cone does not have any linear edge.