Hii !

I need Help For This Exercice :

Either $\displaystyle ABC$ a triangle and $\displaystyle D$ point belonging to $\displaystyle [BC]$ such as :

$\displaystyle \widehat{DAC} = 90$ , $\displaystyle \widehat{BAD} = 30$ , $\displaystyle BD=AC=1$ .

Find / Calculate $\displaystyle CD$ .