Emergency recruitment of database administrators

As shown in the figure, let CE⊥AB be E and AE= 1

AC=2, CE=√3 from RT△ACE,

∴AD= 1,CD=3，

BC=√2*√3=√6 From RT△BCE,

∴BC？ =CA*CD，

That is AC/BC=BC/DC,

And ? ≈ACB =∠BCD,

∴△ABC∽△BCD

∴∠DBC=∠BAC=60，

∴∠DBA= 15