Answer:
C 8.9
Explanation:
all these lines (from the same point of origin, cutting into and through a circle, ending at the far end of the circle they are cutting into) have the same relation of their lengths :
a×(a+b) is the same for all these lines.
with a being the first segment from the point of origin to touching the outside of the circle, and b being the length of the line inside the circle.
so,
4×(4+16) = 8×(8+2) = 80
this is correct for these two lines.
now, the line with the length x is a special case, as it does not really go through a circle, it only touches them.
but the length relation applies also to this line. it is just that the length inside the circle is 0.
so,
x×(x+0) = 80 (the same value as for the other lines)
must be true here too.
=>
x² = 80
x = sqrt(80) ≈ 8.9