A line or a ray - depending on whether the planes are finite or infinite.
The intersection of 2 non-parallel planes is always a line.The intersection of 3 planes doesn't have to be a line, but it can be. If it is,then there are an infinite number of other planes that can also intersect thosethree along the same line.
If each segment intersects exactly two other segment but could, if extended, intersect the third, then the figure is a quadrilateral. Otherwise it is a parallelogram.
a polygon
A closed geometric figure could be called a polylateral - but that is a very obscure word - or simply a polygon. Generally such a figure is referred to in terms of how many lines it is composed of: 3 = triangle 4= quadrilateral 5 = pentagon, etc.
Points, lines and planes are precisely defined terms. These concepts have to be clearly delineated to form fundamental planks in geometry, and that's because as they do. In suggesting that they are undefined, we'd have to suspect everything that was built on them. No geometric figure could be discussed with any certainty unless the elements that make it up are clearly defined and understood.
A straight line, and nothing else.
crash
The intersection of 2 non-parallel planes is always a line.The intersection of 3 planes doesn't have to be a line, but it can be. If it is,then there are an infinite number of other planes that can also intersect thosethree along the same line.
line
If each segment intersects exactly two other segment but could, if extended, intersect the third, then the figure is a quadrilateral. Otherwise it is a parallelogram.
Depending on the location of the intersection, there are many things though could be formed, but to pick commons, it could form a +, T, L
It could be a triangle, a quadrilateral, a pentagon, a hexagon or even an octagon if they are two concave quadrilaterals.
The word there could be an adverb applied to a street or intersection.
If they are all plane faces then there is no such figure. Otherwise it could be a sphere intersected by two planes, an ellipsoid intersected by two planes, a cone intersected by two planes, or one of several other shapes.
by adding a segment
two planes intersect in one line, or the planes could be parallel. by the way there is no such thing as skew planes...
Yes, but then again it depends on what or where they are!