EXPLANATION
Let's see the facts:
Radio antenna height= Adjacent cathetus = 27ft
Support cable attached = θ = 30°
Opposite cathetus = x = unknown
In order to find the value of x, we need to use the Pythagoras Theorem
tg θ = Opposite cathetus / Adjacent cathetus
Now, replacing terms:
tg 30° = x / 27ft
Multiplying both sides by 27:
27ft*tg30° = x
Switching:
x = 27ft * tg30° = 15.6 ft
Answer: 15.6ft is the measurement that is the closest to x