Answer:
|DC| = 9
Step-by-step explanation:
Set up and solve an equation of ratios. This is possible because the upper and lower triangles are similar. AB = 10 and DE = 12, so we can write
20 15
---- = -------
12 |DC|
Then 20 |DC| = 12(15) = 180. Solving for |DC| : |DC| = 180/20 = 9
