Question

Complete each statement with the word always, sometimes, or never.

If two planes intersect, their intersection _______ a line.

Short answer

The sentence is:

If two planes intersect, their intersection isalways a line.

Step-by-step solution

Step 1. Define a line and a plane. 

A line is a straight path of points that has no beginning or end.

A plane is a two-dimensional flat surface that extends to infinity.

Step 2. State the explanation.

If two planes intersect,

Then their intersection is always a line.

Hence, the correct word here is always.

Step 3. State the conclusion.

Therefore, the statement is:

If two planes intersect, their intersection is always a line.