SOLUTION: Sorry heres another one..I got trouble with coordinates. 1. The Three points P(-2,3),Q(1,q) and R(7,0) are collinear. a)Find the value of q b) Find the ratio of lengths

Algebra ->  Length-and-distance -> SOLUTION: Sorry heres another one..I got trouble with coordinates. 1. The Three points P(-2,3),Q(1,q) and R(7,0) are collinear. a)Find the value of q b) Find the ratio of lengths       Log On


   



Question 363820: Sorry heres another one..I got trouble with coordinates.
1. The Three points P(-2,3),Q(1,q) and R(7,0) are collinear.
a)Find the value of q
b) Find the ratio of lengths PQ: QR

Answer by Jk22(389) About Me  (Show Source):
You can put this solution on YOUR website!
P(-2,3),Q(1,q) and R(7,0) collinear if PQ proportional to PR (other possibilities exist) :

PQ = (1-(-2), q-3) = (3, q-3) PR = (9, -3)

we have : PR shall be 3 * PQ (with the x component), hence the y component of PQ has to be : -3/3 = -1, hence q = 2
QR = (6, -2)
PQ/QR is hence 3/6 = 1/2