Question

If P(1,4), Q(9,-2), and R(5,1) are collinear then

• A. P lies between Q and R
• B. Q lies between P and R
• C. R lies between P and Q
• D. none of these

Answer 1

The correct option is C R lies between P and Q

PQ = $\sqrt{{(1-9)}^2+{(4+2)}^2}=10$
QR = $\sqrt{{(9-5)}^2+{(-2-1)}^2}=5$
PR = $\sqrt{{(1-5)}^2+{(4-1)}^2}=5$
$\therefore PQ=PR+RQ$
Therefore R lies between P and Q