A Cone is a 3D geometrical figure and questions related to volume, surface area and slant height are generally asked in the exam.
the following expressions give the general formula of the volume
v= area of base x height
so applying this concept here in the cone the area of the base is a circle with radius r and height is h but since they all are going to a common vertex we need to put additional 1/3
v=1/3* (pi* r^2)*h
and in the same fashion, the curved surface area or lateral surface area is given by a general expression
curved surface area= perimeter of base Xslant height
c.s.a.= 1/2 *2*pi*r*l
and finally total surface area= c.s.a.+ pi*r^2
there is also a use of Pythagoras theorem in slant height
i.e.
l^2= r^2+h^2.
also, there are several questions related to trigonometry and cone combined.
Thanks