If the vector product of a constant vector OA→ with a variable vector OB→ in a fixed plane OAB be a constant vector, then the locus of B is
a straight line perpendicular to OA→
a circle with centre o and radius equal to OA→
a straight line parallel OA→
none of these
|a→×r→|=|c→|
Triangles on the same base and between the same parallel will have the same area.