i)

ii) A square has 4 equal sides. The diagonal cuts the square into two isosceles, right angled triangles.

Let side of Square B = a. By pythagoras's theorem,

Now Square C has area twice Square B.

Area Square B =

Area of Square C =

From the working above, we know

Therefore Area of Square C is (Side C)˛ = where Side C is a side of square C

Perimeter = 4(Side C) = 4(2x) = 8x.

Note: Thank you masters for pointing out that I haven't completed the question. Its very late in my time zone, and I misread the question.