If one vertex of an equilateral triangle of side a lies at the origin and the other lies on the line x−3y=0, the coordinates of the third vertex are
(0,−a2)
(a,0)
a32,a2
a32,−a2
Clearly Q, R are the two positions of the third vertex, P(acos300,asin300),Q(0,a),R(acos300,−asin300)
i.e., P3a2,a2, Q(0,a) R3a2,−a2