Note that the sum of arc CE + arc DB = 360 - 107 -144 = 109°
So CE + DB = 109 (1)
And we have that, by a geometry theorem
measure of angle CAE = (1/2) (arc CE - arc DB) )
21 = (1/2) (CE - DB)
42 = CE - DB (2)
Add (1) and (2)
2CE = 151
CE = 151 / 2 = 75.5°
