30°
Step-by-step explanation:
[tex] \overline {CA} \cong \overline {BD}... (given) \\
\therefore \overset {\frown} {CA} \cong \overset {\frown} {BD}\\[/tex]
(equal chords intercepts equal arcs)
[tex] \therefore \overset {\frown} {AB} \cong \overset {\frown} {CD}\\
\therefore m \overset {\frown} {AB} =m \overset {\frown} {CD}\\
m \overset {\frown} {CD}=30°...(given) \\
\therefore m \overset {\frown} {AB} =30°\\[/tex]
