For this case we have to define trigonometric relations of rectangular triangles that:
- The cosine of an angle is given by the leg adjacent to the angle on the hypotenuse of the triangle.
- The sine of an angle is given by the leg opposite the angle on the hypotenuse of the triangle.
Then, according to the figure we have:

Answer:

Option D
For this problem, I'd use cross-multiplication.
9/12 = x/8.
When cross multiplying, multiply 12*x and 9*8. This leads to a new equation:
12x = 72.
Then you solve as an algebra problem.
*Divide 12 on both sides*
x = 6.
Answer:
wow so what's the question then
<em>Note:</em><em> You missed to add some of the details of the question.
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<em>Hence, I am solving your concept based on an assumed graph which I have attached. It would anyways clear your concept.</em>
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Answer:
Please check the explanation.
Step-by-step explanation:
Given the right angled-triangle ABC as shown in the attached diagram
From the triangle:
Ф= ∠C = 30°
AB = 6 units
BC = y
tan Ф = opp ÷ adjacent
The opposite of ∠C = 30° is the length '6'.
The adjacent of ∠C = 30° is the length 'y'.
As Ф= ∠C = 30°
so
tan Ф = opp ÷ adjacent
tan 30 = 5 ÷ y
1 ÷ √3 = 5 ÷ y
y = 8.7 units
Therefore, the length of the unknown side length 'y' is 8.7 units.