Question

Need help please.

Answer 1

Hi !

BAC is a triangle isocele in B so :  $\widehat{BAC}=\widehat{BCA}=80\°$

The sum of the angles of any triangle is 180°.

$180-80\times2=180-160=20$

$\boxed{\boxed{\widehat{ABC}=20\°}}$