Final answer:
The MOST appropriate method of providing assisted ventilations to a patient who experienced a significant exposure to cyanide and is semiconscious and breathing inadequately is to use a bag-valve mask.
Step-by-step explanation:
The MOST appropriate method of providing assisted ventilations to a patient who experienced a significant exposure to cyanide and is semiconscious and breathing inadequately is to use a bag-valve mask. The bag-valve mask is a device that consists of a self-inflating bag connected to a face mask, and it is used to deliver positive pressure ventilation to the patient. This method ensures that the patient receives enough oxygen to support their breathing and helps to maintain their oxygen levels.