.
Your answer is INCORRECT.
To get the correct answer and the correct solution, us the
Theorem 1. The measure of the angle between a chord and a tangent line to a circle at the endpoint of the chord
is half the measure of the arc stretched by the chord.
This theorem is well known Geometry statement.
See, for example, the lesson
- The angle between a chord and a tangent line to a circle
in this site.
From the Theorem,
5x = ,
which implies
10x = 9x + 20,
x = 20 degrees. ANSWER
Solved.
---------------
In this site, you have this free of charge online textbook on Geometry
GEOMETRY - YOUR ONLINE TEXTBOOK
The referred lesson is the part of this online textbook under the topic "Properties of circles, their chords, secants and tangents".
Save the link to this online textbook together with its description
Free of charge online textbook in GEOMETRY
https://www.algebra.com/algebra/homework/Triangles/GEOMETRY-your-online-textbook.lesson
to your archive and use it when it is needed.