Answer:
Triangle ABC, ∠ABC = 90°, also BD is perpendicular to AC.
∠ACB = x° and ∠CBD = 90 - x
=> ∠ABD = x and ∠BAD = 90 - x
=> ΔABC , ΔADB and ΔBDC are similar.
[tex]=> \frac{BD}{CD} = \frac{AD}{DB} \\\\=> \frac{8}{CD} = \frac{4}{8} \\\\=> CD = \frac{8*8}{4} =16[/tex]
