The real-world problem that is most likely to involve irrational numbers is "finding the diameter of a circle based on the radius." This is because the diameter is calculated as \( 2r \), where \( r \) is the radius. However, if you are trying to find the circumference or area of the circle based on the radius, those calculations introduce π (pi), which is an irrational number.
In general, calculations involving circles (like circumference and area) frequently lead to irrational numbers due to the presence of π.