Angles and the sides across from them have a specific relationship. Th smaller the angle or openness then the smaller the side. The larger the angle the larger the side. Since Angle A opposite side is 10 it is smaller than Angle B whose opposite side is 20. Since Angle C's opposite side is between the two, you can conclude that Angle A < Angle C < Angle B.
We can do the same for the other triangle knowing Angle D is 61 and Angle DCE is 60 (vertical angle theorem). Since a triangle's angles add to 180 then 180-61-60=59. Angle E is 59 degrees and since it is the smallest will have the smallest side CD. Angle DCE is the next largest and its oppposite side of DE will next followed by CE. You can conclude that CD<DE<CE
