Answer:
[tex]CD=7.5\ cm[/tex]
Step-by-step explanation:
step 1
Find the value of AC
we know that
Applying the Intersecting Secant-Tangent Theorem
[tex]AB^{2}=AD*AC[/tex]
we have
[tex]AB=5\ cm[/tex]
[tex]AD=10\ cm[/tex]
substitute the values and solve for AC
[tex]5^{2}=10*AC[/tex]
[tex]AC=25/10=2.5\ cm[/tex]
step 2
Find the value of CD
[tex]CD=AD-AC[/tex]
substitute the values
[tex]CD=10-2.5=7.5\ cm[/tex]
