Answer:
137°
Explanation:
ACD = ACB + BCD
If angle ACD is 165°, then ACB and BCD should add up to 165°.
ABC = 28
Which means when the values for ACD and ACB are replaced in the equation, you would get:
165 = 28 + BCD
You can remove the 28 by subtracting 28 from both sides of the equation
165 - 28 = 28 - 28 + BCD
137 = BCD