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