Geometry help please

First one

A tangent to a circle meets a radius at right angles

So  ABD  =  90°

Second one :

Ths is the intersecting chords theorem....specifically, we have that

9(n + 7)  = 18(n + 1)    divide both sides by 9

n + 7  =  2(n + 1)     simplify

n + 7  =  2n + 2   subtract n, 2  from both sides

n   = 5

Last one

Notice that ABC  =  180  - 47 - 48  =  85°

But ABC  would have to  = 90°   for BC to be tangent

So...the second  answer is correct