help with geometry........

Answer:
DC=2.4
Step-by-step explanation:
let DC=x
AB=4-x
[tex]\frac{3}{4.5} =\frac{4-x}{x} =\frac{4}{x} -\frac{x}{x} =\frac{4}{x} -1\\\frac{4}{x} =\frac{30}{45} +1=\frac{30+45}{45} =\frac{75}{45} =\frac{5}{3} \\5x=4*3=12\\x=12/5=2.4[/tex]