Option a:
is the length of b
Explanation:
The angle of B is
and 
We need to determine the length of b.
First, let us determine the angle of A.
Since, ABC is a triangle, then all the angles add up to 180°
Thus, we have,




Thus, the angle of A is 
Now, we shall determine the length of b using the sine law formula.
The formula for sine law is given by,

where
,
, 
Thus, we have,

Simplifying, we get,

Multiplying both sides by 0.866, we get,

Multiplying the numerator, we have,

Dividing, we get,

Thus, the length of b is 
Hence, Option a is the correct answer.
The expression can be simplified as:
b-8
Answer:
m<c = 104°
m<d = 80°
Step-by-step explanation:
Recall: Opposite angles of a cyclic quadrilateral are supplementary. Therefore, their sum equals 180°. Thus:
m<c + 76° = 180°
m<c + 76° - 76° = 180° - 76° (subtraction property of equality)
m<c = 104°
m<d + 100° = 180°
m<d +100° - 100° = 180° - 100° (subtraction property of equality)
m<d = 80°