I don't know.. what happens next?
Answer:
E.) 1
Step-by-step explanation:
Firstly we will solve for L.H.S.
L.H.S. =
Since we know that
is the inverse of
.
So we can say that;

Now For R.H.S.

Since we can rewrite
as
.
Now we can say that the R.H.S. is;

Now we add the fraction and get;

Now according to trigonometric identity;

So, 
Here,
and
=
<em> </em>
L.H.S. = R.H.S.
Hence 
Answer:
10 inches
Step-by-step explanation: