Apologies. I was incorrect. it can be 5..... or 4.695, or 5.299, or 5.335 or 6. I assumed the columns represented 4 equal rectangles with a width of 2.5 in the square.
The same that you have to assume the angles are 30, 60, and 90 to come up with X=5.
It depends on the angles that you assume (Not provided in OP)
No Sir...
All Right Angle Triangles have two legs and a Hypotenuse.
The “congruent” rectangles make use of two Legs and two Hypoteni (SIC?) to equal 10.
See the diagram above.
The Hypotenus legs are more than 2.5.
The Adjacent Legs are less than 2.5.