Barry M. answered 01/17/20
Professor, CalTech Grad; Many Years Tutoring Math, SAT/ACT Prep, Chem
In traveling from 1 PM to 1:30, the minute hand moves from the top of the clock to the bottom (12 down to 6). This is exactly half of the circumference. Since C = 2 pi r, the answer will be pi X r, and r is the radius = 11 ft.
So it's 11 pi r