Hello!
Let's think of this large triangle as a whole. If we add up the angles, we have 115°. The adjacent side to this angle is 9 feet. Let's try finding the opposite side. The tangent deals with these two.
tan115≈2.14
Therefore, x/9=2.14
We multiply both sides by 9 to find x.
x=19.26
Now let's find the length BC and subtract it from 19.26 to find our length. As we will deal with opposite and adjacent sides, we will find the tangent.
tan45=1
This means x/9=1
Therefore, BC=9
Now we can subtract from 19.26
19.26-9=10.26
Therefore, this length is 10.26 feet
I hope this helps!
