Answer:
[tex]x=6.93\ units[/tex]
Step-by-step explanation:
To better understand the problem see that attached figure with letters
we know that
In the right triangle BCD
[tex]cos(C)=4/x[/tex] ----> equation A
we know that
In the right triangle ABC
[tex]cos(C)=x/12[/tex] -----> equation B
equate equation A and equation B
[tex]\frac{4}{x}=\frac{x}{12}\\ \\x^{2}=48\\ \\x=6.93\ units[/tex]
