parallel planes
They are mutually perpendicular. However, they need not intersect: if they are in different planes, they will not intersect.
Yes. If two planes are not coincident (the same plane) and are not parallel, then they intersect in one straight line.
The angle between two planes when the planes intersect at a point is the acute angle fixed by the normal vectors of the planes.
No. Two planes may be parallel and so may not intersect. Also, any line is the intersection of infinitely many planes, not just two.
Two planes intersect at a line
A line. When two planes intersect, their intersection is a line.
No, two planes do not intersect in exactly one plane unless the planes are exactly overlapping, making one plane. In Euclidean Geometry two planes intersect in exactly one line.
In geometry, two planes intersect in a line. The only time this is not true is if the two planes are parallel to each other.
parallel planes
Two distinct planes will intersect in one straight line.
They are mutually perpendicular. However, they need not intersect: if they are in different planes, they will not intersect.
Yes. If two planes are not coincident (the same plane) and are not parallel, then they intersect in one straight line.
The angle between two planes when the planes intersect at a point is the acute angle fixed by the normal vectors of the planes.
The intersection of two planes is a line.
Two planes that intersect are simply called a plane to plane intersection. When they intersect, the intersection point is simply called a line.
Two planes intersect at a line. The line where they intersect pertains to both planes. In the same manner, if infinitely many planes intersect each other at the same line, then that line pertains to the infinitely many planes.