Answer:
x ≈ 12.33
Explanation:
given 2 secants from an external point to the circle, then the product of the measures of one secant's external part and the entire secant is equal to the product of the measures of the other secant's external part and that entire secant, that is
DC × (DC + x) = BC × (BC + AB) , that is
6(6 + x) = 5 × (5 + 17) = 5 × 22 = 110
36 + 6x = 110 ( subtract 36 from both sides )
6x = 74 ( divide both sides by 6 )
x = 12.33 ( to the nearest hundredth )