Check the picture below.
CD is a diameter, that means the arcCABD = 180°.
since CD and AB are both parallels, the arcs they make are congruents, namely arcCA = arcBD.
let's say arcCA is hmmmm "x".
[tex]\bf \widehat{CA}+\widehat{BD}+\widehat{AB}=180\implies x + x +74 = 180\implies 2x+74=180 \\\\\\ 2x=106\implies x=\cfrac{106}{2}\implies x=53[/tex]
