Postulate Example 2.6 Plane-Line Postulate ER If two points lie in a plane, then F the line containing them lies in the plane. 2.7 Plane Intersection Postulate If two planes intersect, then their intersection is a line. S Notes: Points D and E lie in plane R, so DE lies in plane R. The intersection of plane S and plane T'is line l. Extra Practice In Exercises 1 and 2, state the postulate illustrated by the diagram. 1. 4 If then B B