Sin angle that equals the 1/2 value is the 30 degree on the 1st Quadrant.
The angle of 30 degree on the 3rd Quadrant is equivalent to (formula and circle in the 1st photo) 180 + 30 = 210°.
So theta = 210° (3rd Quadrant) = 30° (1st Quadrant).

Now just transfer the cos 30° to the 3rd Quadrant and the signal will be negative (as shown in the 2nd photo attached).
Option C:
is the value of a and b
Explanation:
Given that the expression 
We need to determine the value of a and b
Let us consider the term
and take the prime factorization of the term 648
Thus, we have,
648 divides by 2,

324 divides by 2,

162 divides by 2,

81 divides by 3,

27 divides by 3,

9 divides by 3,

Thus, we have,

Therefore, equating the powers of 2 and 3, we get,

Hence, the value of a and b is 3 and 4
Thus, Option C is the correct answer.
4+X/X=X
4+X=X*X
when the answer fits the equation, the answer is correct
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Answer:
0.8
Step-by-step explanation:
3(5x+2)+10=4
=15x+6+10=4
After this step you subtract 6 from each side and then subtract 10 from each side and then after that you divide 15x on each side which will give you 0.8.