Respuesta :

semsee45

Answer:

19.5

Step-by-step explanation:

If C is the midpoint of AD, and AC=13 then AD = 2 x 13 = 26

If B is the midpoint of AC, then AB = 13 ÷ 2 = 6.5

So BD = AD - AB = 26 - 6.5 = 19.5