find the value of the variable using sine cosine or tangent. if necessary round to the nearest tenth.

In order to find the value of x, use the the sine function, a follow:
sine 49° = opposite side/hypotenuse
sine 49° = x/16
solve the previous equation for x, as follow:
sine 49° = x/16 multiply both sides by 16
16·sin49° = x
16·0.75 = x
12.07 = x
x ≈ 12.1