The vertex of an isosceles triangle having angle different from the two equal angles is called the apex of the isosceles
The common polygon vertex at the top of a pyramid or
the vertex of a cone is also called an apex.
See alsoApex Graph
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Cite this as:
Weisstein, Eric W. "Apex." From MathWorld--A
Wolfram Web Resource. https://mathworld.wolfram.com/Apex.html