Question

State the postulate that verifies AB is in plane Q when points A and B are in Q. Postulate 1: A line contains at least two points. Postulate 1a: A plane contains at least three points not all on one line. Postulate 1b: Space contains at least four points not all on one plane. Postulate 2: Through any two different points, exactly one line exists. Postulate 3: Through any three points that are not one line, exactly one plane exists. Postulate 4: If two points lie in a plane, the line containing them lies in that plane. Postulate 5: If two planes intersect, then their intersection is a line.

Answer 1

Answer: Postulate 4: If two points lie in a plane, the line containing them lies in that plane.

That is because two points, call them A and B, always form a line, and so, given that they form the line AB and they are in the plane Q, the line AB is in the plane Q.