The total degrees of a circle is 360. You are given every angle but one. You would need to subtract 360 from the given angles of 27, 103, 50, and 35. The sum is 215. Subtract 360 and 215 and you get 145. That is the missing angle of CD. CDE includes DE, which is 27. You would need to add 145 (CD) and 27 (DE) to get the total degree of CDE: 172°.