--Answer--
[tex]5\sqrt{2}[/tex] or 7.0710... (7.1)
--Explanation--
If you look closely the triangle on the left could be moved to the space on the right of the shape.
Then, the edges would be 10 inches (top) and 5 inches (sides).
From there, you multiply 10 x 5 to get 50. If you want the square root, you do [tex]\sqrt{50}[/tex] which is how I got 7.071067812, or 7.1, which was rounded to the nearest tenth.
