A. Circle just did it on apex!
The cross section will be a triangle with base 2 feet and a vertical height of 9 feet.
The answer depends on the angle at which the axis of the cone intersects the cross-sections.
cone
Depends on the way you cut the cone, but the outline is either an ellipse or a parabola.
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Circular when looking up at it
By definition, the circular cross-section of a cone changes linearly in width as you go along its axis. By definition, the cross-section of a prism is constant along its axis. So, by definition, a cone prism is an impossible shape.
The strongest shape in nature is the triangle. A traffic cone has a cross section of a triangle. This would give it strength especially when knocked into by the traffic.
A. Circle just did it on apex!
The vertical cross section of a right vertical cone is a triangle if that cross section is taken from the vertex. Any other vertical cross section will reveal a hyperbola (with endpoints on the base of the cone). A link can be found below.
The cross section will be a triangle with base 2 feet and a vertical height of 9 feet.
Circle
The answer depends on the angle at which the axis of the cone intersects the cross-sections.
If it a right cone then it is a circle, otherwise an ellipse.
Circle
A "cross section" is what occurs when you "slice" a given shape in a particular way, so that you can visualise the shape in two parts (with 2 new faces). The cross section is the surface (face) of the side which you have just sliced. E.g If you imagine a cone, with the circular base resting on a surface. You now slice the cone horizontally, so that you now have a very small cone (on top), and a "truncated cone" (2 circular faces, top one slightly smaller, with sloping sides joining them) below. The "cross section" is the top face of the truncated cone, and the lower face of the small cone (both cross sections are the same!). i.e they are the new "sides" that you have created. These new "faces" are both circular, so if you were to find the area you would use the formula pi*radius^squared = area.