Answer:
Step-by-step expThis is the concept of trigonometry, the value of x will be calculated as follows;
sin theta=[opposite]/[hypotenuse]
theta=x
opposite=16 units
hypotenuse=21 units
thus;
sin x=16/21
hence;
x=arcsin(16/21)
x=49.63
x=50 (to the nearest degrees)