OX = XB = BY = OY =OP Let OX = R (radius of the larger circle) then OB= R√2 Similarly PQ = MQ = QR = r (radius of the smaller circle) then BQ = r√2 ∴ BP = r + r√2 and BP =OB −OP = R √2 − R R√2 − R = r + r √2 R( √2 − 1) = r(√2 + 1) ⇒ r = R( √2 − 1)2 r = R(3 − 2√2 ) ∴