Answer:
y = 8√3 ≈ 13.86
Explanation:
The relevant trig relations are ...
Tan = Opposite/Adjacent ⇒ tan(30°) = x/12
Cos = Adjacent/Hypotenuse ⇒ cos(30°) = 12/y
To find the value of y, we can multiply the second equation by y/cos(30°):
y = 12/cos(30°) = 12/(√3/2)
y = 8√3 ≈ 13.86
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Additional comment
x = 12·tan(30°) = 4√3 ≈ 6.93