Locus of Triangle Centroid
Let nCr–1 = 28, nCr = 56 and nCr+1 = 70. Let A(4cost, 4sint), B(2sint, –2cost) and C(3r – n, r2 – n – 1) be the vertices of a triangle ABC, where t is a parameter. If (3x – 1)2 + (3y)2 = α, is the locus of the centroid of triangle ABC, then α equals :