Answer:
40°
Step-by-step explanation:
arc AB has twice the measure of the inscribed angle BCA that intercepts it, so we have the relation ...
(6x-50)° = 2(2x)°
2x -50 = 0
2x = 50
So, angle BCA has measure 50°. Since AC is a diameter, angles BCA and BAC are complementary. Thus ...
m∠BAC = 90° - m∠BCA = 90° - 50°
m∠BAC = 40°
