Correct answer is: distance from D to AB is 6cm
Solution:-
Let us assume E is the altitude drawn from D to AB.
Given that m∠ACB=120° and ABC is isosceles which means
m∠ABC=m∠BAC = 
And AC= BC
Let AC=BC=x
Then from ΔACD , cos(∠ACD) = 
Since DCB is a straight line m∠ACD+m∠ACB =180
m∠ACD = 180-m∠ACB = 60
Hence 

Now let us consider ΔBDE, sin(∠DBE) = 

Answer:
B. cos−1(StartFraction 11.9 Over 14.5 EndFraction) = θ
Step-by-step explanation:
From definition:
cos(θ) = adjacent/hypotenuse
The adjacent side respect angle GFE (or θ) is side FE, and side FG is the hypotenuse. Replacing with data and isolating θ:
cos(θ) = 11.9/14.5
θ = cos^-1(11.9/14.5)
Answer:
tan−1(StartFraction 6.9 Over 9.8 EndFraction)
Step-by-step explanation:
tan−1(StartFraction 6.9 Over 9.8 EndFraction)
tan = opp/adj = 9.8/6.9
tan -1 = 1 / tan = 1 / (9.8 /6.9) = 6.9 /9.8