Answer: If two planes intersect, then they intersect in exactly one line.
Explanation:
- A plane is a two-dimensional flat level surface which extends up to infinity .
When two lines(one-dimensional) intersect , they intersect at a point (no dimension)
When two planes intersect then their intersection is a line which is one -dimensional.
When two planes do not intersect then they are called parallel.
Therefore , if two planes intersect, then they intersect in exactly one line.