A Cone
The answer is - a cone.
A hemisphere
A cone.
a cone
One flat face and one curved face.
Cone.
a sphere :)
If you have one flat face and I have one curved face, which one of us is the 3d shape? Anyway, a 3d shape with pne f;at, circular face and one curved face could be: a section of a sphere or a section of an ellipsoid cut by a plane parallel to one of its axes, a section of a paraboloid or a cone. There are probably other shapes.
flat
A cone
2D = semi circle 3D = hemisphere