if abc~ dec , what is the length of de? Please help

Answer:
B) 12
Step-by-step explanation:
Given:
ΔABC ~ ΔDEC
AB ~ DE
AC ~ DC
BC ~ EC
We will just use ratios and substitute DE as x:
[tex]\frac{AB}{AC} =\frac{DE}{DC} \\\\\frac{16}{20} =\frac{x}{15} \\\\20x=240\\\\x=\frac{240}{20} \\\\x=12[/tex]
DE = 12