Step-by-step explanation:
first of all, as the sum of all angles in a triangle is always 180°, the missing angle B is
B = 180 - 89 - 30 = 61°
the law of sine is
a/sin(A) = b/sin(B) = c/sin(C)
where the sides are always opposite of the associated angles.
14/sin(61) = AB/sin(30) = BC/sin(89)
BC = 14×sin(89)/sin(61) = 16.00451901...
so, 16 is the correct answer.
