base of triangle - T height of triangle equilateral = sqrt (3)/2 * base = {sqrt(3)/2}*T The area of the equilateral triangle - 1/2 (base)* (height) = 1/2 *(T) *({sqrt(3)/2}*T). Now, Perimeter of square = S . Therefore one side will be - S/4 . (square has 4 equal sides.) Therefore Area of square is (...