Pythagorean Theorem states that, if a triangle is a right triangle,

then the sum of the squares of the lengths of the legs a and b equals

the square of the length of the hypotenuse c.

The expression is:  

             (Substitute )

                  (Evaluate power: )

                              (Add:)

                             (Calculate the value using a calculator)

The width of the widest rectangular panel is about 2.657 m.