Answer:
Step-by-step explanation:
According to the Parallelogram definition, every Parallelogram have a pair of congruent sides. In this case, Namely and
(not listed as an option)
And the opposite angles are congruent too.
So
sin 30=14/x
x=14*2
x=28
and
x=√{28²-14²}
x=14√3