Two unit squares share the same center. The overlapping region of the two squares is an octagon with perimeter 3.5. What is the area of the octagon?

Question

I don't know how to do this. Could you please help me?

Answer 1

I will assume the octagon is regular, so each side is 3.5/8 = 7/16.

Now just divide the octagon into eight isosceles triangles, each with base 7/16 and vertex angle 45°.

The area of each triangle is easy to do, and just multiply it by 8.