AB = 18 BC=8 CD=5
Let's call E that point at the other end of x, so x=DE.
Secant Secant theorem says
CE × CD = AC × BC
and since CE = CD + DE, AC = AB + BC
(CD + DE) CD = (AB + BC) BC
Substituting,
(5 + x)(5) = (18 + 8) (8)
5 + x = (26)(8)/5
x = -5 + (26)(8)/5 = 183/5 = 36.6
Answer: 36.6, last choice
