Chọn câu đúng.

$\widehat {CBD} = \widehat {CAD}$        

$\widehat {CBD} < \widehat {CAD}$

$\widehat {CBD} > \widehat {CAD}$       

$\widehat {CBD} =2.\widehat {CAD}$ .

$\Delta OAD = \Delta OCB$          

$\Delta ODA = \Delta OBC$          

$\Delta AOD = \Delta BCO$

$\Delta OAD = \Delta OBC$ .

$\Delta OAD = \Delta OCB$          

$\Delta ODA = \Delta OBC$          

$\Delta AOD = \Delta BCO$

$\Delta OAD = \Delta OBC$ .

${60^0}$       

${80^0}$

$120^\circ$

${100^0}$

$CE \bot \;AB$

$BD\; \bot AC$

$DC = BC$

Cả A, B đều đúng.

$CE \bot \;AB$

$BD\; \bot AC$

$DC = BC$

Cả A, B đều đúng.

$120^\circ$

$90^\circ$

$60^\circ$    

${100^0}$