why is a line undefined

Question

anonymous · Answer

what do you mean?

anonymous · Answer

The question asks "Why is a line an undefined term?". I wondering the answer is because it has no width or depth, or because it contains an infinite amount of points.

anonymous · Answer

If slope is undefined in slope formula, then x-x1=0. 

m=y-y1/x-x1=0  
m=y-y1/0 
m=undefined

anonymous · Answer

In the coordinate plane, a point is named by an ordered pair, (x,y). LINE (an undefined term) In geometry, a line has no thickness but its length extends in one dimension and goes on forever in both directions.

anonymous · Answer

|dw:1383183374280:dw| this would be a undefined line on a graph. it is undefined because it has an infinite point that could be "y" but the "x" axis would always stay the same.

directrix · Answer

@OneTwoThreeFour 

In Euclidean Geometry, the three undefined terms are point, line, and plane.