Answer:
(h) ST, ∠S, ∠R
Explanation:
In general the Law of Sines is applicable when you have two angles and a side. The solution of the triangle will be unique if the given side is opposite the largest angle.
These conditions are met in choice h.
x/sin(S) = ST/sin(R)
x = sin(S)·ST/sin(R) = sin(34°)·7/sin(92°)
x ≈ 3.917
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Additional comment
Here's why the other choices don't work.
(f) These values would require sin(R) = 15.3/8.1×sin(38°) ≈ 1.163. No angle has a sine of this value, so no triangle can be formed with these values.
(g) The given angle is between the given sides, so the Law of Cosines is needed for solving the triangle.
(j) Three angles are given, but no sides are given. The lengths of the sides, including x, cannot be determined.