Question

Solve the triangle for x.

Answer 1

Answer:

90.4°

Step-by-step explanation:

Use Law of Cosines to solve:

12² = 9² + 8² - 2(9)(8)Cos X

  144 = 81 + 64 - 144Cos X

     -1 = -144Cos X

         -1/144 = Cos X

            Cos^-1 (-1/144) = X

                     X = 90.39789056°

Answer 2

For this case we have that the law of cosine is given by:

$c ^ 2 = a ^ 2 + b ^ 2-2 (a) (b) * cos (x)$

Where:

$c = 12 \ ft\\a = 8 \ ft\\b = 9 \ ft$

We replace:

$12 ^ 2 = 8 ^ 2 + 9 ^ 2-2 (8) (9) * cos (x)\\144 = 64 + 81-144 * cos (x)\\144 = 145-144 * cos (x)\\-1 = -144cos (x)\\cos (x) = \frac {1} {144}\\x = cos ^ {- 1} (\frac {1} {144})\\x = 89.60 \ degrees$

Answer:

Option B