The complete question in the attached figure
we know that
<span>An<span> exterior angle</span></span><span> is one that has its vertex at an outer point of the circumference.
</span><span>The measure of the external angle is the semi-difference of the arcs that it covers.
in this problem the external angle is </span>∡(9x-5)°
and
the semi-difference of the arcs that it covers is (1/2)*(158°-64°)=47°
then
(9x-5)=47-------> 9x=47+5----------> 9x=52--------> x=5.78°
the answer is
x=5.78°
we know that
<span>An<span> exterior angle</span></span><span> is one that has its vertex at an outer point of the circumference.
</span><span>The measure of the external angle is the semi-difference of the arcs that it covers.
in this problem the external angle is </span>∡(9x-5)°
and
the semi-difference of the arcs that it covers is (1/2)*(158°-64°)=47°
then
(9x-5)=47-------> 9x=47+5----------> 9x=52--------> x=5.78°
the answer is
x=5.78°