Question 549713
square 
Area = 4cm^2

side = 2

Use Pythagoras theorem
diagonal = hypotenuse 

diagonal ^2= side1^2+side2^2

diagonal^2=2^2+2^2

diagonal^2=8

diagonal = sqrt(8)

the radius of the sircle will be 1/2 the diagonal
sqrt(8)/2
=2sqrt(2)/2
=sqrt(2)
m.ananth@hotmail.ca