Hey there :)
The measure of arc BEC is 290°
The total measure of a circle is 360°
Therefore, the measure of arc BAC will be:
= Circle - m of arc BEC
= 360° - 290°
= 70°
Notice they have asked for the angle BAC
The measure of the minor arc is equal to the measure of the central angle
m BAC = ∡ BAC
70° = 70°