Respuesta :

altavistard

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

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