Respuesta :

Answer:

10.5 cm

Step-by-step explanation:

Since we know that O lies on AB we know that:

  1. The distance from the midpoint of OA to O is 6 cm (12/2).
  2. The distance from the midpoint of OB to O is 4.5 cm (9/2).

You can add 6 to 4.5 to get 10.5 cm.