What is the shape of a horizontal cross section of a cone?

Answer 1

A cross-section refers to the end of a prism, cones are not prisms. A shape like a cylinder is a prism. Hexagonal prisms have hexagonal cross-sections, and pentagonal prisms have pentagonal cross-sections. It's that simple.

But for the sake of what the question COULD mean, I'll try and help.
The easiest way to find the shape of a part of a three-dimensional object is to tear it apart (literally) and look at its net. The curved surface area of the cone looks like a rectangle when the cone is split open.

Here are some formulas for the fun of things:

Volume of cone = 1/3πr2h

Surface area of cone =

πrs +

πr2

π = Circumference (Perimeter of the circle) / Diameter (Length from one end of the circumference to the other end passing through the centre)

r = Radius (Half the diameter)

s = Side length (Up the side of the cone to the top)