Answer:
The equation you should solve to find b is:
Option D. sin 35° / 9 = sin 40° / b
Step-by-step explanation:
m<A=35°
m<B=40°
a=9
b=?
We can use the Law of sines:
sin A / a = sin B / b
Replacing the given values:
sin 35° / 9 = sin 40° / b
This is option D.