Let's 'd' is

dia of circle=side of the square.

Area of blue=area of square - area of circle

=d^2-pi/4d^2..... (i)

Area of red =pi/4 d^2.... (ii)

Ratio of area of red/area of blue is

=(ii) /(i)

Pi/4 d ^2

=----------------

d^2-pi/4 d^2

Pi/4

=-------- (by removing d^2)

1-pi/4

=22/6 (by putting the value of pi =22/7)

So ratio is 22 to 6

ie 22:6 or 3.6666666666.... :1