Answer:
A
Step-by-step explanation:
First, we need to find the unknown angle of the triangle.
40 + 20 = 60
180 - 60 = 120
So the unknown angle is 120.
Then, we can use the law of sines to create a proportion.
sin(120)/8 = sin(40)/a
Then, we can simplify this.
a is about 5.9, or answer choice A.