Step 1
we know that
The perimeter of a square is equal to
P=4*b
where
b is the length side of a square
Find the perimeter of the square picture
b=4 in
P=4*4=16 in
Step 2
Find the maximum radius of the circular frame
we know that
the perimeter of a square frame is equal to the circumference of the circular frame
the circumference is equal to
[tex]C=2\pi r[/tex]
[tex]16=2\pi r[/tex]
[tex]8=\pi r\\\\r=\frac{8}{\pi}[/tex]
r=2.5 in
therefore
the answer is
the maximum radius of the circular frame is 2.5 in