According to the meaning of the question, the dotted line crosses AB at O point and CD at G point respectively.

Because ∠ ogd' = ∠ ogd = 130 (you can know that these two angles are the same by folding a piece of paper yourself).

According to the angle relationship: ∠ OGC =180-130 = 50; ∠CGD'= 130 -50 =80