If R, S, and T are collinear and RS + ST = RT, which of the following is true?

A.T is between R and S.
B,RS = RT
C.S is the midpoint of .
D.S is between R and T.

Question

If R, S, and T are collinear and RS + ST = RT, which of the following is true?

A.T is between R and S.
B,RS = RT
C.S is the midpoint of .
D.S is between R and T.

debbieg · Answer

What do you think?

anonymous · Answer

c.

debbieg · Answer

Well, c is not complete, but I'm assuming it should say "S is the midpoint of RT". So what if the situation looks like this?

|dw:1377794775906:dw|

debbieg · Answer

Then R, S, and T are collinear and RS + ST = RT, but it's clear that S is not the midpoint.

anonymous · Answer

thanks deb so it must be D.

debbieg · Answer

Yeah, I think so. :) Remember, if you can think of a SINGLE counter-example to a general statement, then it isn't true in general. :)

anonymous · Answer

can you answer this too?? 

Which of these are undefined terms?
point
segment
plane
angle

debbieg · Answer

Hmmmm.... I'm not really sure. My intuition tells me one over the other 3, but I'm not completely sure what the question is getting at.

What do you think it is?