Answer:
112°
Step-by-step explanation:
Arc CD is part of arc BCD, which is intercepted by the inscribed angle A.
Based on the inscribed angle theorem on circle, the sum of arc CD and CB is twice the measure of angle A.
That is:
CD + CB = 2(129°)
CD + 146 = 2*129
CD + 146 = 258
Subtract 146 from both sides to find CD
CD + 146 - 146 = 258 - 146
CD = 112°
