Answer:
11
Step-by-step explanation:
Find the length of the hypotenuse of the right triangle with sides 9 and 6
[tex]a^{2} +b^{2} =c^{2} \\9^{2} +6^{2} =c^{2} \\81+31=c^{2} \\\sqrt{117} =c[/tex]
Use c and the height 2 to find the hypotenuse of the triangle with the dotted line
[tex]\sqrt{117} ^{2} +2^{2} =c^{2} \\117+4=c^{2} \\221=c^{2} \\11=c[/tex]
the dotted line is 11
