Question

1. Find the value of x, rounded to the nearest tenth A. 3.7 B. 4.4 C. 8.9 D. 4.2

Answer 1

Answer:

C 8.9

Step-by-step 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