Respuesta :
Answer:
they intersect exactly one line , if two planes intersect.
Step-by-step explanation:
We need to find the correct option to complete the given statement
"If two planes intersect, then they intersect in exactly _____ line(s)."
Since, a plane is determined by 3 non-co-linear points. In this case the three points are a point from each line and the point of intersection.
Hence, they intersect exactly one line , if two planes intersect.
