From the given figure
The rectangle has a width of 3 and its length is the hypotenuse of a right triangle with legs 5 and 7
Then we will find at first the hypotenuse of the triangle using the Pythagoras Theorem
[tex]\begin{gathered} L=\sqrt[]{7^2+5^2} \\ L=\sqrt[]{49+25} \\ L=\sqrt[]{74} \end{gathered}[/tex]
Now, to find the dotted line we will do the same with the length and the width of the rectangle
[tex]\begin{gathered} D=\sqrt[]{L^2+W^2} \\ L=\sqrt[]{74},W=3 \\ D=\sqrt[]{(\sqrt[]{74})^2+(3)^2} \\ D=\sqrt[]{74+9} \\ D=\sqrt[]{83} \\ D=9.110433579 \end{gathered}[/tex]
Round it to the nearest tenth
The length of the dotted line is 9.1
