Answer:
The missing area is 28 square inches
Explanation:
see the attached figure with letters to better understand the problem
we know that
The area of triangle is given by the formula
In this problem
In each side of the square there are two triangles with the same area, because they have the same base and the same height
so
Group terms
----> equation A
we have that
----> equation B see the picture
substitute equation B in equation A
therefore
The missing area is 28 square inches