(A) Let foot of origin on variable line is P ⇒ (0, 0) and (α, β) subtends right angle at P. ⇒ Locus of P is circle assuming (0, 0) & (α, β) as diameter. ⇒ Required locus is (x – 0)(x – α) + (y – 0)(y – β) = 0 ⇒ Required locus is x2+y2 – αx – βy = 0