$AB=r \sqrt 2 \Rightarrow sd cung AB=90^ \circ \Rightarrow \widehat {ACB}=45^ \circ$
$AC=r \sqrt 3 \Rightarrow sd cung AC=120^ \circ \Rightarrow \widehat {ABC}=60^ \circ$
$\widehat {BAC}=180^ \circ-45^ \circ-60^ \circ=75^ \circ$
- Tienanh tx yêu thích