Q bisects segment PR, PQ=3y, and PR=42 find y and QR?

Question

Can someone please explain with detail what does it mean when it says Q bisects? does that mean it is a point in the middle, or what?

an answer would be nice too, so i can make sure i get it right

Answer 1

To bisect a segment is to cut it in half.  So, yes, Q is a point in the middle of segment PR.

Since point Q cuts the segment PR in half, that means that segment QR has the same length as segment PQ.

|----3y----|----3y---|

|-----------|-----------|

P........Q..........R

|----------42---------|

From the picture above, we get the equation:

3y + 3y = 42

6y = 42

y = 7