Answer:
2 sqrt(5) = DC
Step-by-step explanation:
(whole secant) x (external part) = (tangent)^2
the whole secant = 4+4+2 = 10
The external part is 2
We are looking for the tangent
10 * 2 = DC ^2
20 = DC ^2
Take the square root of each side
sqrt(20 ) = DC
sqrt( 4*5) = DC
2 sqrt(5) = DC
