3

Part of 1965 Spain Mathematical Olympiad

Problems(1)

Length of an spiral

Source: Spanish Mathematical Olympiad 1965 P3

A disk in a record turntable makes

100

revolutions per minute and it plays during

24

30

seconds. The recorded line over the disk is a spiral with a diameter that decreases uniformly from

29

11.5

cm. Compute the length of the recorded line.

lengthsgeometry