Answer:
[tex]\frac{(a-b)^2+b^2}{a^{2}}[/tex]
Step-by-step explanation:
see the attached figure to better understand the problem
we know that
The area of the square is
[tex]A=x^{2}[/tex]
where
x is the length side of the square
step 1
Find the area of the outer square (A_o)
we have that
[tex]x=a\ units[/tex]
substitute in the formula
[tex]A_o=a^{2}\ units^2[/tex]
step 2
Find the area of the inner square (A_i)
we know that
The length side of the inner square is equal to the hypotenuse of a right triangle
so
Applying Pythagoras theorem
[tex]x^{2}=(a-b)^2+b^2[/tex]
Remember that
[tex]A_i=x^2[/tex]
so
[tex]A_i=(a-b)^2+b^2[/tex]
step 3
Find the ratio of the area of the inner square to the area of the outer
[tex]ratio=\frac{A_i}{A_o}[/tex]
substitute the values
[tex]ratio=\frac{(a-b)^2+b^2}{a^{2}}[/tex]