Final answer:
In the JumpSTART triage system, a child with the described condition should have their leg stabilized and then wait for medical assistance, indicating they fall into the 'yellow' or delayed care category.
Step-by-step explanation:
According to the JumpSTART triage system, which is used for pediatric patients in mass casualty incidents, a child who is conscious, alert, breathing, has bilateral radial pulses, and presents with a severely angulated leg that is not bleeding, would be triaged as yellow, indicating delayed care. Thus, the correct action to take is to stabilize the child's leg and wait for medical assistance. There is no active bleeding that requires immediate pressure, and since the child is stable with a patent airway, they do not require immediate transportation or further assessment of airway, breathing, and circulation at this moment according to the JumpSTART criteria.