Answer:
Step-by-step explanation:
<u><em>The picture of the question in the attached figure</em></u>
we know that
The measure of the external angle is the semi-difference of the arches it covers.
so
Remember that the diameter divide the circle into two equal parts
In this problem
TN is a diameter
we have
----> because is half the circle (TN is a diameter)
---> is given
substitute
0.75
just divide 9 by 12