The minute hand of a wall clock is 7 cm long. How far does the tip of that hand travel between 4:00 and 4:30? (Take π = 22/7.)

In half an hour the minute hand sweeps half a turn, so the tip travels half the circumference of a circle of radius 7 cm: (1/2) × 2 × (22/7) × 7 = 22 cm. The traps: 44 cm is a whole turn, that is a full hour; 14 cm is the straight-line gap between the tip's start and finish positions (the diameter), not the curved path it actually travels; 11 cm halves the journey once too often.