Solve similar triangles
Solve for x.

Answer:
x = 12
Step-by-step explanation:
Apply Thales' theorem
[tex]\frac{ED}{CB} =\frac{AD}{AB}[/tex]
[tex]ED=x[/tex]
[tex]\frac{x}{6} =\frac{20}{10}[/tex]
[tex]x=\frac{(20)(6)}{10} =12[/tex]
Hope this helps