The AC is dimeter of circle D, means that AD and BD are radius of circle D.
Consider the triangle ABD, side AD is congurent to side BD. So opposite of side AD and side BD are equal.
[tex]\angle ABD\cong\angle BAD[/tex]
Determine the measure of angle BAD (or angle BAC) by using anle sum property of triangle.
[tex]\begin{gathered} \angle BAD+\angle ABD+\angle ADB=180 \\ 2\angle BAD=180-66 \\ \angle BAD=\frac{114}{2} \\ =57 \end{gathered}[/tex]
Thus measure of angle BAD (or angle BAC) is 57 degree.
Answer 57 degree.
