i need a step to step process pls :(

Answer:
About 29.09 units
Step-by-step explanation:
First, you need to find the measure of angle A. Since the interior angles of a triangle must add up to 180 degrees, A+63+101=180, and A is 16 degrees. Now, you can use the law of sines to find AB.
[tex]\dfrac{9}{\sin 16}=\dfrac{A}{\sin 63} \\\\\\A=\dfrac{9 \cdot \sin 63}{\sin 16}\approx 29.09[/tex]
Hope this helps!