Consider the points P(3,7), Q(−2,4) and R(5,−1) taken in the order P,Q,R. What is the sign of the determinant 3−2574−1111 and hence the orientation of the triangle?
a) Positive; vertices are clockwise
b) Zero; vertices are collinear
c) Positive; vertices are counter-clockwise
d) Negative; vertices are clockwise