Question

The intersection of two planes is _____ a line.

Always
Sometimes
Never

Answer 1

The intersection of two planes is always a line

Answer 2

The answer is Somtimes

Explanation:

When you have two planes whose intersection is not the empty set, you have two posibilites:

- The two planes are the same. In this case you don't have a line as the intersection of them, but it is again a plane.

-The two plane s are not the same . Then the intersection must be a line by an incidence axiom.