Line Intersection Postulate
Postulate: If two lines intersect, then there intersection is exactly ONE point.
Use the 
tool to create two intersecting lines. Then use the 
tool to show the intersection of the two lines. Now add a third line that intersects the first two lines in this same intersection point. (These are called concurrent lines!)
tool to create two intersecting lines. Then use the tool to show the intersection of the two lines. Now add a third line that intersects the first two lines in this same intersection point. (These are called concurrent lines!)