Let other two sides of rhombus are x−y+λ=0 and 7x−y+µ=0 then O is equidistant from AB and DC and from AD and BC ∴|−1+2+1|=|−1+2+λ|⇒λ=−3 and |−7+2−5|=|−7+2+µ|⇒µ=15 ∴ Other two sides are x−y−3=0 and 7x−y+15=0 ∴ On solving the eq n s of sides pairwise, we get the vertices as ,(1,2),(