Since
and
, we have

So, the equation becomes

The solutions to this equation are 4 and -5/2, so I'm afraid there's a typo in your question.
I believe it is c idk the question really doesn't make that much sense
Answer:
7776
Step-by-step explanation:
Yes.
Since we are given the lengths of 2 sides with the angle in
between, therefore by cosine law we can only construct 1 triangle from this. By
stating the angle in between, this constricts the possible number of triangles
that can be formed into 1.
By calculation, the length of the 3rd side is
calculated using cosine law:
c^2 = a^2 + b^2 – 2abcosθ
c^2 = 10^2 + 8^2 – 2(10)(8)cos40
c = 6.44 cm
ANSWER:
1 triangle
The length of the rectangle would be 94m.