Question

Find the radius of a circle in which an inscribed square has a side of 8 inches.

x =

Answer 1

Use this to find D=2r , knowing that s=8
\[
D^2= 2 s^2
\]
Then find \[
r=\frac D2\]

Answer 2

4sqrt2

Answer 3

D is the diagonal of the square
You can work it out from pythagoras - or use the well known fact that diagaonal of square = side * sqrt(2)
(This is the same as @eliesaab said above - in a slightly different way)

You can also see that D is the diameter of the circle - so the radius is D/2