A circle is formed when a cone intersects a plane.
Explanation:
A cross section is the process where a surface is shown when a straight cut is made by something. In the question given when a cone is intersected by a plane horizontally the shape of the cross - section is a circle . On the other hand when the cone is intersected vertically by a plane the shape of the cross- section will be a triangle. Hence the shape of the cross section depends according to the cut.
Cross section is basically used to find what is there inside the object.
