Answer:
[tex]x = \sqrt{12} = 3.464[/tex]
Step-by-step explanation:
[tex]AC=AD+DC=13\\\text{Because ABC is a right triangle then}\\AB^2=AD.AC\\\Rightarrow AB^2=1 \times 13=13\\\Rightarrow AB = \sqrt{13}\\\text{In the right triangle ABD, since Pythagoras we also have}\\AB^2=AD^2+BD^2\\\Rightarrow BD^2=AB^2-AD^2\\\Rightarrow x^2= 13 - 1=12\\\Rightarrow x = \sqrt{12} = 3.464.[/tex]
