Four points A, B, C, and D are coplanar, but only two at a time are collinear. Suppose a line is drawn through each pair of points. How many lines can you draw?

a)0
b)2
c)4
d)6

Question

Four points A, B, C, and D are coplanar, but only two at a time are collinear. Suppose a line is drawn through each pair of points. How many lines can you draw?

a)0
b)2
c)4
d)6

anonymous · Answer

How many straight lines can you draw through these dots? I've drawn 1 for you

anonymous · Answer

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anonymous · Answer

Each line has to touch 2 dots.

directrix · Answer

There are 4 choice for the first point and then 3 for the second point. 
That give 4*3 = 12 lines but includes each line twice. 
Line AB, for example, also is counted among the 12 as Line BA.

So, take 1/2 of 12 and that is the answer.

@paigeyyy1