Use the Pythagorean Theorem to find the missing length. Round your answer to the
nearest tenth.

In this triangle it is clear that the unknown side x is the hypotenuse of both the triangles that are being formed . So , let us take any one of the triangles and with it's length let us find the length of their hypotenuse which is side x .

= 5² + 5² = x² ( according to the pythagorean theorem the square on the hypotenuse will be equal to the sum of the squares on the other two legs )

= 25 + 25 = x²

= 50 = x²

= 7.0710678119 = x

But they have given that we have to round it off to the nearest tenths , so ;

= 7.0710678119 will be equal to = 7.10

= 7.1 = x

Therefore , the length of the unknown side x = 7.1 .