What is an apex in math? The apex is either the vertex that is located at the highest point or the highest point of a geometric figure. The figure below shows apexes for the cone and the pyramid.
In the figure above, the pyramid has 5 vertices. However, the apex is the vertex located at the highest position.
The cone does not technically have a vertex if we strictly apply the definition of vertex. However, it has a highest point called apex. Mathematicians and math textbooks also like to call the highest point of a cone "vertex".
You may see geometric figures that appear to have more than 1 apex such as the rectangular prism. However, apex applies only to geometric figures that will yield only 1 apex to avoid ambiguity.