Answer:
[tex]m\angle ABC=47^o[/tex]
Step-by-step explanation:
we know that
The measure of the external angle is the semi-difference of the arches it covers
so
[tex]m\angle ABC=\frac{1}{2}[arc\ DE-arc\ AC][/tex]
substitute the given values
[tex]m\angle ABC=\frac{1}{2}[142^o-48^o][/tex]
[tex]m\angle ABC=47^o[/tex]
